Horse riding in camargue national park

If you go to Camargue, the French national park, you can't loose a ride on a native horse. I found my horse  (named Lesley) in the farm-hotel Cacharel, next to a wild zone of the part. The price for 2 hour was 28 euro.  When the guide proposed me to "gallop" and I agreed I did not know what it could happen.... no way to stop!