The European Commission is investigating the drugmaker for having possibly obstructed an antitrust inspection at its offices this past January. The allegation focuses on the drugmaker’s refusal to let inspectors examine and copy documents until French authorities produced a national search warrant, according to the commission.

The European antitrust regulator raided Sanofi headquarters in France as part of a wider inquiry into the industry. Under European antitrust laws, companies have an obligation to cooperate with the commission’s inspectors, including providing full access to documents.

The commission is conducting an anti-trust probe out of concern over the dwindling number of new patents and drugs entering the market. As part of the inquiry, it raided the offices of a number of drugmakers, looking for evidence that behavior in patenting new drugs and litigating unnecessarily may have put a dampener on competition in the pharmaceutical markets in Europe.

Sanofi says the probe is the result of a procedural dipuste. “The controversy with the commission centers on a question of procedure concerning the handing over of a single document requested by the European Commission and actually delivered by Sanofi-Aventis during the inspection,” the drugmaker said in a statement.

“With respect to this document, (the company) wished to protect its specific interests in connection with an American proceeding and asked, before turning over the document to the European Commission, that the order of the French judge be notified, which has always been the practice in France.”