Have no idea how your crows behave. The ones I hunt aren't easy either. If they're coming to where you want them to, and are well hid, I'd think it would just be a matter of getting them in range.
We find where a huntable number want to be, hide upwind of them a quarter or half mile and call them to us. That way we're not diving them away from where they want to be. Some days work better than others.
Having never hunted crows in France, can’t say for sure, but here is my take:
First, good concealment and no motion in your hide is very important. Crows are smart and have great eyesight!
Next, put yourself where the crows are. Food sources and flyways, for example. Put in the time to scout out the best spots. Talk to farmers who have crows bothering their operations, etc.
Lastly, consider using a flapper such as the FF6. https://www.flightlinedecoys.co.uk/store/ff6-multibird-flapper-detail I’ve had great success with mine.
Good luck and keep us posted on your progress.
Demi
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