I know this is an old thread, but I was looking for something similar myself earlier this year and we found Firs Lake France, despite COVID we managed to go still and had a great week, the fish are in great condition and accommodation is lovely. My 7 year old said it was the best holiday of his life :) there is a little stock pond too where the kids can fish for loads of small carp.
<a href="https://www.firslakefrance.com/exclusive-carp-fishing-france-with-accommodation/">Carp fishing France family accommodation</a>
