I can't speak for France specifically but if it's anything like the UK and Ireland then farming families are dis-incentivized to sell land because its costs not

I can't speak for France specifically but if it's anything like the UK and Ireland then farming families are dis-incentivized to sell land because its costs nothing to hold, and always increases in value. As a farmer you might not even own the land you work on but rent it for the season, and large corporations don't work well with that kind of uncertainty.