If you are submitting to festivals, read the fine print. I have come across two festivals in the last month that not only want your submission fee, but then claim the worldwide, perpetual right to do anything they want with your film. I have complained to FilmFreeway about this, but nothing happened. See if you can find an article from The Hollywood Reporter from a few years ago about festivals like the Oaxaca Film Festival.
My films have shown in about 30 festivals worldwide, I have had great fun at the ones I could attend, and have been a judge at festival in NYC, so this is not sour grapes, just a heads up.