The constraint is served on the debtor by registered letter with acknowledgement of receipt or by bailiff’s deed. On pain of nullity, the bailiff’s writ or the registered letter shall mention :
1° The reference of the constraint ;
2° The amount of the sums claimed and the nature of the allowances, grants and other benefits in question or the date of the administrative penalty;
3° The time limit within which opposition must be lodged;
4° The address of the competent court and the formalities required for bringing the matter before it.
The bailiff will notify the creditor organisation of the date of service within eight days.