Are you in Italy by chance? This lock looks very similar in principle to a garage door lock of the same brand (Prefer) I had while living there: the cylinder drives two plates that move a pair of rods, one at the top and one at the bottom – except that the garage door had a wider body and the cylinder allowed the key to be inserted from either side. I see the Prefer 6610 is also being sold in France.
In my case, I found a replacement garage door lock at the local hardware store – OBI, Brico IO, Granbrico and the like. At least one of them might also have a matching lock for your gate. You’ll most likely replace not only the cylinder but then entire lock assembly – the piece you removed from the gate and took apart. What you want to look out for:
- drive for two rods with the same distance between the two rods (in locked/unlocked state, respectively)
- cylinder that fits through the faceplate of your lock
- compatible mount points
- compatible external dimensions