Infringing mass (masse contrefaisante)

The infringing mass (masse contrefaisante) is the set of products or acts found to be infringing, which serves as the basis for calculating compensation. The concept was developed by the case law and is not defined in the Intellectual Property Code, but it governs the application of Article L. 615-7, since the negative economic consequences and the infringer's profits are calculated on this basis.

Determining the infringing mass

Three steps follow one another. First, identify the product references actually covered by the asserted claim, since patent infringement sometimes concerns only part of a range. Next, define the period, which begins with publication of the application or, for a reseller, with the knowledge required by Article L. 615-1, paragraph 3, of the Code, and ends when the acts cease. Finally, quantify the volumes, using the accounting documents obtained through a saisie-contrefaçon or through a disclosure order.

Recurring disputes

The defendant challenges the infringing mass by excluding references not covered by the claim, sales made outside the territory covered by the patent, exported products, free samples and sales the patent holder would have lost in any event. Where the infringing element is only one component of a larger product, the debate turns on the share of the price attributable to it, a question close to the one raised by component-level licensing in royalty matters.

The infringing mass in practice

The court frequently rules in two stages: a judgment on the principle of infringement, together with an order for the disclosure of documents and an interim payment, then a decision on the amount. An expert may be appointed to reconstruct the volumes. A claimant who neglects this reconstruction falls back on lump-sum compensation based on the royalties that would have been due, an amount that is by construction harder to increase.

Key points

The infringing mass is built like an accounting file, reference by reference and period by period. It is prepared from the time of the seizure, because missing documents cannot be recovered at the assessment stage. Each limit adopted, whether territorial, temporal or technical, shifts the final amount significantly.

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This glossary entry is general in scope and does not constitute legal advice.

Dhenne Avocats litigates patent disputes before the Paris Judicial Court, the Paris Court of Appeal and the Unified Patent Court. Where the question arises in a real case, the useful moment is almost always before proceedings are issued.

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