Law No. 2018-771 was published on September 5th and reviews the administrative penalties relating to the detachment of personnel in France.
What the law says : any employer who has not issued a certificate of secondment or has not designated a representative, may be fined up to 4,000 € per detached employee. In case of reiteration within two years from the date of notification of the first fine, a fine of up to 8,000€ may be applied.
The total amount of the fine may not exceed 500,000€.