Transfer of co-owned patent or trademark rights: is the consent of the other co-owner required?

Co-ownership of patents or trademarks often arises in collaborative innovation, particularly among inventors, business partners, or startup co-founders. While common, this legal arrangement entails a number of significant legal and strategic complexities especially when one co-owner seeks to transfer their share without informing the other.

A recent ruling issued by the Paris Judicial Court on 7 February 2025 clarifies the obligations of co-owners in the context of IP right transfers. The decision reinforces the importance of legal formalism and notification procedures. This article analyses the practical and legal consequences of such transfers, along with strategic guidance for rights holders.

Legal framework for IP co-ownership

Patent co-ownership: transfer regulations

Article L. 613-29 of the French Intellectual Property Code (IPC) allows a patent co-owner to transfer their share at any time. However, other co-owners benefit from a statutory right of first refusal, exercisable within three months of receiving formal notification by means of a bailiff’s act.

This requirement is further reinforced by Article 815-14 of the French Civil Code, which obliges the transferring party to disclose essential information: the proposed sale price, terms, and identity of the prospective buyer.

Trademark co-ownership: legal constraints and duties

Although less strictly codified than patent co-ownership, trademark co-ownership is recognized under Article L. 712-1 IPC. In the absence of a prior agreement between co-owners, the unilateral sale of a share without notification or consent may be deemed wrongful particularly if it deprives the other co-owner of financial rights or commercial opportunities.

The “Ares Trailer” case (Paris Judicial Court, 7 February 2025)

Background and key facts

In case number RG 21/07225, the Paris Judicial Court adjudicated a dispute between two co-inventors of a trailer system, who jointly owned a patent, a design, and a trademark registered under the name “Ares Trailer.” One of the co-owners transferred all IP rights to a third-party company without notifying the other, and the assignment documents were later found to contain a forged signature.

Key takeaways from the decision

The Court declared the contested assignments null and void due to lack of consent, emphasizing that even a lawful transfer of a share requires prior notification of the other co-owner.

However, the acquiring company escaped liability due to its good faith, as recognised under the doctrine of appearance. The co-owner who executed the transfer was ordered to pay €17,500 in damages for moral and financial harm caused to the other co-owner.

Legal risks of unilateral transfers without notification

Failing to comply with co-ownership rules regarding notification exposes the transferring party to significant legal risk, including:

• Annulment of the transfer, especially where consent is lacking or the transaction is tainted by fraud;
• Civil liability for breaching co-ownership obligations;
• Loss of revenues or commercial opportunities for the other co-owner;
• Litigation that may be prolonged, costly, and publicly damaging.

While a good-faith purchaser may retain the rights acquired, the assignor remains liable for having disregarded their legal obligations.

Best practices for managing IP co-ownership

To ensure compliance and mitigate risk, we recommend that co-owners of patents or trademarks:

• Formally notify all co-owners of any proposed transfer or licensing arrangement;
• Draft a comprehensive co-ownership agreement specifying procedures for transfer, licensing, and dispute resolution;
• Conduct a full review of title history and rights transfers prior to acquiring an interest in co-owned IP;
• Seek legal counsel proactively when contemplating any transaction affecting shared rights.

Conclusion

The co-ownership of intellectual property rights requires careful legal governance. The failure to notify other co-owners prior to a transfer even a partial one can lead to nullity of the transaction and potential damages. The “Ares Trailer” case provides a compelling precedent that reinforces the necessity of transparency, legal precision, and proactive planning when managing co-owned IP assets.

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