SUJET :

Je recherche le bloqueur du chariot du rail d’écoute du génois. Quelqu’un sait je peux me le procurer.  

Looks like you have a 32mm Amiot Track Stop, (1 and 1/4 inch on this side of the Atlantic) measure your track to make sure. 
Adjustable Track Stop: Ami 32T-03:
Unique Adjustable Track Stop for Amiot 32mm T-Track features SS Pin stop on spring hinge. Used to limit the movement of other components, especially jib and genoa Cars. Anodized aluminum Track Stop is 1 9/16" (40mm) long x 2 3/8" (60mm) wide, and has a 3/8" (10mm) plunger Pin.   

Try Rig-Rite, Warwick Rhode Island USA, WWW.RigRite.com
I recently used them for new halyard exit plates for my Elite 32 (Feeling 920) Francespar mast. I've also used them for boom parts. Turn around time was good every time I used them, they shipped in a day or two and I had the parts in three days. 

Many thanks John !  for this amazing supplier. 
I will refer to him in our Support section : clubfeeling1090.fr/sav

I call them, not aviable.