I would like to know if I need to have the rights for commercial usage for a photo that I want to enter in a photo competition. Consider this scenario: I take a photo of someone (e.g. a model) and they grant me a non-exclusive, non-commercial right to use/distribute the photo online and in other media. If I want to enter this photo in a photo competition (where prizes can be won). This way, I'm not directly making money off the photo, but if I win a prize I would potentially have a monetary benefit. Does this qualify as commercial usage of the photo? Does it matter if there are no prizes? And if there are prizes, does it matter if they are monetary or material prizes (e.g. photo equipment)? I live in Germany, I'm interested in the situation for both national and international competitions.
I know that some competitions ask the participants to grant the host commercial usage rights as well, so those competitions are out of the question.