When the labour inspector or controller has reason to believe, based in particular on the conditions under which the work of all or some of the employees employed in a company is organised, that this employment constitutes a breach of both the prohibition on concurrent employment provided for in article L. 8261-1 and the derogation provided for in article L. 8261-3, he may ask the employer to require the designated employees to provide a written attestation certifying that they are not in breach of these same provisions or of those relating to working hours.