Here in France, at least in our region, the season starts the 15th may. In fact buck are active during May, cool down all June long and are in full swing rut from the 15th July to the 15th August, especially in August, depends on weather.
I was after a nice buck for three years and eager to connect with him at the opening of the season but no luck. The weather is too hot and wind whirling no end. I made only 2 attempts and will wait for the rut to outsmart this foxy buck. A piece of luck that my hunting partners let me this buck though I am refusing to harass him every week.
Good luck