In a judgment delivered on 18 June 2026, the French Court of Cassation provided further clarification on the evidentiary requirements applicable to fee-sharing agreements relating to contingency fees between lawyers.

In the case in question, a lawyer sought payment from a fellow lawyer for a portion of the success fee received in connection with a matter that had been subcontracted to the latter. As no written fee-sharing agreement had been concluded between the two lawyers, the claimant relied on a witness statement from a third lawyer who was not involved in the dispute. This statement said that the two lawyers had agreed to divide the success fee equally.

The French Court of Cassation was therefore required to rule on whether a witness statement issued by a third party could serve as initial proof in writing (“commencement de preuve par écrit”) of a fee-sharing agreement relating to a success fee between lawyers.

The Court answered in the negative. Firstly, it was held that Article 10 of the Law of 31 December 1971, which states that a success fee can only be claimed if it has been included in a fee agreement, also applies to relationships between lawyers where a matter has been subcontracted. Secondly, the Court reiterated that, pursuant to Article 1362, paragraph 1 of the French Civil Code, commencement of proof in writing consists of any written document originating from the person disputing the legal act or their representative which renders the alleged facts plausible.

As the witness statement did not originate from the lawyer against whom the claim for payment had been made, the Court of Cassation overturned the appellate court’s decision to order her to pay €128,831.87 as her share of the success fee.

This decision highlights the importance of documenting any fee-sharing agreement between lawyers and confirms that a witness statement from a third party cannot constitute commencement of written proof within the meaning of Article 1362 of the French Civil Code.