The participatory procedure agreement shall, on pain of nullity, be contained in a writing that specifies:
1° Its term;
2° The subject matter of the dispute;
3° The documents and information necessary for resolving the dispute or putting the dispute in order and the procedures for exchanging them.
4° Where applicable, the documents countersigned by lawyers that the parties agree to draw up, under conditions laid down by decree in the Conseil d’Etat.