The complete set in detail

F6426B
Marianne l'engagée : Economic Mail for France 20 gr.), grey, selfadhesive stamp, signature "phil@poste"

F6427B
Marianne l'engagée : "Lettre Verte" (economic mail 20 gr.), green, selfadhesive stamp, signature "phil@poste"

F6428B
Marianne l'engagée : Priority Mail for France 20 gr., red, selfadhesive stamp, signature "phil@poste"