Attorney-Client Privilege for Foreign Patent Agents and European Patent Attorneys 

Attorney-client privilege refers to the protection of confidential communications made for the purpose of obtaining or providing legal advice. Application of and exceptions to this privilege are fact-based determinations made on a case-by-case basis. The components of attorney-client privilege include a client’s request for legal advice, disclosure of facts to obtain legal advice, a lawyer's request for facts to provide such advice, and provision of the advice. See Upjohn Co. v. United States, 449 U.S. 383, 389 (1981); see also Fed. R. Evid. 501. In the context of in-house counsel, the “client” is the legal corporate entity and not the corporation’s individual officers, directors, shareholders, or employees. See Upjohn, 449 U.S. at 390-91. Exact standards vary by jurisdiction. Caution is warranted when including third parties in attorney-client communications. 

Limitations and exceptions to privilege  

Not all communications are protected by attorney-client privilege. Underlying facts are discoverable. Privilege cannot, and should not, be used to protect facts from being discovered. Id. at 395. Disclosure is routinely upheld by courts to protect against clients and attorneys “privileging” everything in order to obfuscate the truth. 

Communications that do not involve a lawyer (or a nonlawyer not acting under the direction of a lawyer in a legal capacity) are not protected. See, e.g., LKQ Corp. v. Kia Motors Am., Inc., No. 21-C-3166, 2023 WL 3200236, at *3 (N.D. Ill. May 2, 2023). Simply forwarding a message to an attorney or referencing legal topics does not, by itself, create privilege. See, e.g., Cormack v. United States, 117 Fed. Cl. 392, 397 (2014). It also does not apply when communications take place in the presence of unauthorized third parties. In re Teleglobe Commc’ns Corp., 493 F.3d 345, 631 (3d Cir. 2007).  

Even when the privilege initially applies, it may later be lost, either intentionally or inadvertently. See Fed. R. Evid. 502. Only the client can “waive” the privilege. In the patent context, a common example of waiver is disclosing an opinion of counsel to defend against a charge of willful patent infringement. Knorr-Bremse Systeme Fuer Nutzfahrzeuge GmbH v. Dana Corp., 383 F.3d 1337, 1345 (Fed. Cir. 2004). 

Privilege can also be destroyed through disclosure to a third party. Genentech, Inc. v. U.S. Int’l Trade Comm’n, 122 F. 3d 1409, 1415 (Fed. Cir. 1997). For instance, sharing a previously privileged communication with a third party may destroy the privilege over that and related communications. Id. Additionally, the privilege is lost when communications are made in furtherance of a crime or fraud. Unigene Labs., Inc. v. Apotex, Inc., 655 F.3d 1352, 1358-59 (Fed. Cir. 2011). It is important to note that simply marking a document “attorney-client privileged” does not, on its own, guarantee that the privilege applies. When applicable, however, it is a good practice.  

Patent agents and the complexity of privilege 

The question of privilege becomes more complex when the legal professional is a non-attorney, such as a patent agent or European patent attorney. (For the purposes of this discussion, we will refer to both as “patent agents.”) This nuance was first addressed in Sperry v. Florida, a foundational lawsuit in establishing the legal status of U.S. patent agents. Sperry was not a licensed attorney but was a registered patent practitioner at the United States Patent and Trademark Office (USPTO). See 373 U.S. 379 (1963). As a patent agent, Sperry prepared and prosecuted patent applications for clients before the USPTO in Washington, D.C., but his office was in Florida. Because Sperry was not admitted to the bar of any state, the Florida Bar sued him for the unauthorized practice of law. The Supreme Court ruled in Sperry’s favor, holding that patent agents are permitted to engage in legal work when representing their clients before the USPTO. The Court emphasized that patent practitioners “are not simply engaging in law-like activity,” but are indeed practicing law. In re Queen’s Univ. at Kingston, 820 F.3d 1287, 1296 (Fed. Cir. 2016); Sperry, 373 U.S. at 383. This decision served as a pivotal precedent, setting the stage for future courts to extend attorney-client privilege to patent agents.  

The scope of patent agent privilege was not explicitly addressed until In re Queen’s University at Kingston. See In re Queen’s Univ., 820 F.3d at 1287. Queen’s University was the plaintiff in a patent infringement lawsuit and had previously worked with U.S. patent agents to prosecute several of its patents. During discovery, the defendant sought communications between the University and its patent agents. However, Queen’s University refused to produce certain documents, asserting that the communications were protected by the attorney-client privilege. The district court rejected this argument, finding that because the patent agents were not lawyers, attorney-client privilege did not apply. Queen’s University sought review of this holding. In a landmark ruling, the Federal Circuit granted the petition and constructed a privilege for patent agents. The court held that “communications between non-attorney patent agents and their clients that are in furtherance of the performance of these tasks, or ‘which are reasonably necessary and incident to the preparation and prosecution of patent applications or other proceedings before the Office involving a patent application or patent in which the practitioner is authorized to participate’ receive the benefit of the patent-agent privilege.” Id. at 1301. This privilege is limited in scope and applies only to communications directly tied to tasks that patent agents are authorized to perform under 37 C.F.R. § 11.5(b)(1), such as preparing and prosecuting patent applications, advising clients about whether and how to file applications, and drafting communications for Patent Trial and Appeal Board proceedings. Id. To the contrary, “communications with a patent agent who is offering an opinion on the validity of another party’s patent in contemplation of litigation” are not privileged. Id. at 1301-02. 

It is important to note, however, that communications with patent agents are privileged when they are working “under the supervision of . . . staff patent attorneys.” W.R. Grace & Co. v. Pullman, Inc., 446 F. Supp. 771, 776 (W.D. Okla. 1976); accord Cuno, Inc. v. Pall Corp., 121 F.R.D. 198, 204 (E.D.N.Y. 1988). Thus, privilege applies to U.S. patent agents “so long as [they are] registered by the Patent office.” In re Ampicillian Antitrust Litig., 81 F.R.D. 377, 394 (D.D.C. 1978) (quoting Vernitron Med. Prods., Inc. v. Baxter Labs., Inc., 186 U.S.P.Q. 324, 325 (D.N.J. 1975)). Moreover, a patent agent employed in a corporate patent department “may qualify as a ‘subordinate’ of an attorney if [he or she] is working at the direction of and under the supervision of an attorney.” Hercules, Inc. v. Exxon Corp., 434 F. Supp. 136, 146 (D. Del. 1977) (quoting Congoleum Indus., Inc. v. G.A.F. Corp., 49 F.R.D. 82 (E.D. Pa. 1969)). 

Foreign patent agent privilege in the U.S. 

Challenges in applying attorney-client privilege in U.S. litigation often emerge when foreign patent agents are involved in patent prosecution, opinion drafting, or related legal activities. To assess whether such communications are protected from discovery, U.S. courts typically engage in a two-step analysis: (1) Determine whether U.S. or foreign privilege law governs, and (2) assess whether the governing law recognizes privilege for the specific type of communication involved. Align Tech., Inc. v. 3Shape A/S, Nos. 17-1646-LPS, 17-1647-LPS, 2020 WL 1873026, at *2 (D. Del. Apr. 15, 2020) (citing In re Queen’s Univ., 820 F.3d at 1302). This second step requires analysis of the precise activity performed by the patent agent. 

Courts have developed three approaches for determining whether U.S. or foreign law applies. The most common is the “touch-base” test, which considers whether the communication touches base with the United States. See Duplan Corp. v. Deering Millikan, Inc., 397 F. Supp. 1146, 1169-70 (D.S.C. 1974); see also AstraZeneca LP v. Breath Ltd., No. 08-1512, 2011 WL 1421800, at *5-8 (D.N.J. Mar. 31, 2011). For example, if the communication relates to U.S. patent prosecution or related matters, then U.S. privilege law applies. If it does not, courts defer to the law of the country with the most direct and compelling interest in the communication. VLT Corp. v. Unitrode Corp., 194 F.R.D. 8, 15-16 (D. Mass. 2000). The second approach applies a balancing test to identify which jurisdiction has the strongest interest in maintaining the confidentiality of the communication. Id. The third, the comity-plus-function approach, focuses on the national law of the foreign practitioner and examines whether privilege attaches based on the professional function the agent is performing. See Smith Kline Beecham Corp. v. Apotex Corp., 193 F.R.D. 530, 535 (N.D. Ill. 2000). Regardless of the method used, the court must ultimately analyze the scope of privilege under the applicable law and whether the agent was engaged in authorized conduct. This can become quite complicated. For example, in Golden Trade, S.r.L. v. Lee Apparel Co., the court analyzed the privilege laws of Norway, Germany, and Israel in reaching its decision. See 143 F.R.D. 514 (S.D.N.Y. 1992). 

The following sections discuss how attorney-client privilege has been addressed in U.S. litigation when applied to foreign patent agents (including European patent attorneys) from various countries. 

Germany 

Communications involving German patent agents (Patentanwälte) have been recognized as privileged under German law, and U.S. courts have deferred to that law when evaluating privilege for German patent agents. In 2M Asset Mgmt., LLC v. Netmass, Inc., the court upheld privilege for communications between Netmass and its German patent agent, recognizing that German law provides protections analogous to U.S. attorney-client privilege. No. 2:06-CV-215, 2007 WL 666987, at *3 (E.D. Tex. Feb. 28, 2007). Because the subject matter concerned patent issues governed abroad and the foreign jurisdiction had the most direct and compelling interest, the court applied German law. Similarly, in Softview Comput. Prods. Corp. v. Haworth, Inc., the court concluded that communications between German patent agents and U.S. counsel regarding a European Patent Office application were privileged. No. 97-CV-8815, 2000 WL 351411, at *11 (S.D.N.Y. Mar. 31, 2000) (“Accordingly, communications to Haworth’s German patent agents are protected by the attorney-client privilege to the same extent as communications to domestic attorneys.”). See also Santrade, Ltd. v. General Elec. Co., 150 F.R.D. 539, 547 (E.D.N.C. 1993) (finding documents privileged under German law). The court deferred to German law, which recognized confidentiality obligations for patent agents. These decisions demonstrate that when a communication relates to foreign patent prosecution and the foreign country has strong secrecy protections, U.S. courts will honor those protections under principles of comity. See Cadence Pharm., Inc. v. Fresenius Kabi USA, LLC, 996 F. Supp. 2d 1015, 1022 (S.D. Cal 2014) (finding documents to be privileged under German law). 

Japan 

U.S. courts have recognized that Japanese law provides an attorney-client privilege to Japanese patent agents (known as benrishi). In VLT Corp. v. Unitrode Corp., the court addressed a letter from a U.S. attorney to a benrishi and held that Japanese law treats such communications as privileged. 194 F.R.D. at 12. The court cited Article 197 of the Japanese Civil Procedure Code, which grants benrishi the same confidentiality protections as licensed attorneys (bengoshi). Further reinforcing this conclusion, in Eisai Ltd. v. Dr. Reddy's Labs., Inc., the court acknowledged that Japanese law formally extends privilege to communications involving benrishi, especially in matters relating to patent prosecution and associated legal advice. 406 F. Supp. 2d 341, 341-43 (S.D.N.Y. 2005). The court upheld privilege as a matter of comity, noting that Japan affords broad protection to such communications. Id. at 344. 

France 

Prior to 1992, French law did not provide any confidentiality protections for patent agents. In 1990, France created the formal category of Industrial Property Attorneys, introducing a limited obligation of professional secrecy in 1992. Bristol-Myers Squibb Co. v. Rhone-Poulenc Rorer, Inc., 188 F.R.D. 189, 194 (S.D.N.Y. 1999). Between 1992 and 2002, this privilege applied only to those attorneys, but it was not absolute and failed to support a claim of privilege. Thus, U.S. courts consistently found that communications with French patent agents lacked the necessary protection for privilege to apply. 

In Bristol-Myers Squibb Co. v. Rhone-Poulenc Rorer, Inc., the court declined to recognize privilege for communications with French agents who were not operating under the authority of a U.S. attorney. Id. at 199-201. French law did not fully protect patent agents from having to reveal confidential client communications during French legal proceedings. Thus, even if French law recognized a duty of confidentiality, it was not strong enough to stop a French court from forcing disclosure. 

France amended its Intellectual Property Code in 2004 via Article L. 422-11. This established a true evidentiary privilege for Industrial Property Attorneys, but only if they maintain professional independence. This excludes practitioners employed by corporations or influenced by external entities, and U.S. courts have adopted this interpretation. See Commissariat à l’Energie Atomique v. Samsung Elecs. Co., 245 F.R.D. 177, 186 (D. Del. 2007). 

Switzerland 

Courts in the U.S. generally have declined to recognize attorney-client privilege for Swiss patent agents, primarily due to the limited scope of confidentiality protections under Swiss law. In In re Rivastigmine Patent Litig., for example, the court refused to extend privilege to communications with Swiss patent agents. 237 F.R.D. 69, 74-75 (S.D.N.Y. 2006). It emphasized that under Swiss law at the time, judges could compel disclosure of confidential communications if the interest in disclosure outweighed the interest in secrecy. This conditional standard fell short of the absolute protection required under U.S. attorney-client privilege. As in Bristol-Myers, the court reiterated that a general duty of confidentiality is insufficient to warrant U.S. privilege protection. 

Effective in 2011, Switzerland enacted the Patent Attorney Act, which formally imposed a professional secrecy obligation on patent attorneys and allowed them to refuse disclosure in legal proceedings.ⁱ While that law strengthened confidentiality protections in Switzerland, it remains unclear whether U.S. courts will extend recognition to foreign agents based solely on those reforms. 

Britain 

U.S. courts generally have recognized attorney-client privilege for communications with British patent agents when the communications relate to patent prosecution in the United Kingdom. In Duplan Corp. v. Deering Milliken, Inc., the court held that communications with British patent agents were privileged when they concerned the prosecution of British patent applications. Duplan Corp., 397 F. Supp. at 1171. The court relied on Section 15(1) of the British Civil Evidence Act 1968, which explicitly extended legal professional privilege to registered patent agents acting within their professional role. Id. at 1169. This recognition was rooted in comity and the principle that U.S. courts should defer to foreign privilege law where the foreign jurisdiction has the most direct and compelling interest in the communications. 

The Netherlands 

U.S. courts have taken a favorable view toward recognizing privilege for Dutch patent agents, as Dutch law provides sufficient confidentiality protections. In Organon, Inc. v. Mylan Pharms., Inc., the court evaluated whether documents prepared by Dutch patent agents were protected from disclosure. 303 F. Supp. 2d 546, 547, 549-50 (D.N.J. 2004). The court held that Dutch law recognized a confidentiality privilege applicable to patent agents so long as the communications were within the scope of their traditional function. Because the documents at issue fell within that category and were made for the purpose of obtaining legal advice related to patent prosecution, the court honored the asserted claim of privilege. Id. at 550. 

Scope of privilege 

As underscored by the court in Philips N. Am. LLC v. Fitbit LLC, even when a jurisdiction recognizes privilege for patent agents, the protection does not automatically attach to all communications. 583 F. Supp. 3d 251, 255, 259 (D. Mass. 2022). In that case, the documents at issue were not protected by privilege, as they did not relate to prosecution before the USPTO. Accordingly, courts must still assess the nature of the conduct involved to determine whether the communication falls within the scope of the privilege. Id. at 268-70. This case highlights the importance of examining the type of work the patent agent performed. Even if a jurisdiction (whether U.S. or foreign) provides for privilege, courts can closely analyze whether the agent’s role involved legal tasks within the traditional scope of patent preparation and prosecution. Only then will the privilege be maintained. 

This heightened scrutiny creates practical consequences for companies working with patent agents, especially in cross-border matters. It emphasizes the need for clearly outlining the patent agent’s function and ensuring that their contributions are strictly authorized. Failing to observe these distinctions risks losing privilege protection, even when the jurisdiction at issue formally recognizes it. As such, organizations should proactively structure their communications to reflect the agent’s legal role and document their involvement accordingly.ⁱⁱ 

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ⁱ World Intellectual Property Organization (WIPO) Standing Committee on the Law of Patents, Information on Cross-Border Aspects of Confidentiality of Communications Between Clients and Patent Advisors (Nov. 5, 2011). 

ⁱⁱ See International Association for the Protection of Intellectual Property, Report of the AIPPI Special Committee Q163: Attorney Client Privilege and the Patent and/or Trademark Attorney Profession (March 2002) (recommending that privilege should apply to patent agents admitted to local and regional offices).