I think the poster narrowed that to the typical invitation to meet and have lunch.
I wouldn't "invite" people to help me move or do some handywork, it would rather be called "asking for help". And I know there are other kinds of invitations: playing board games, video games or music, making arts, group sex or whatever other activities one can think of that can be done in groups and yes in that case you might not expect the host to cook necessarily. My experience is that in France people would generally bring something anyway or at the very least ask what they should bring, even if it is just a bag of crisps and a few beers when meeting someone at their place.
I wouldn't "invite" people to help me move or do some handywork, it would rather be called "asking for help". And I know there are other kinds of invitations: playing board games, video games or music, making arts, group sex or whatever other activities one can think of that can be done in groups and yes in that case you might not expect the host to cook necessarily. My experience is that in France people would generally bring something anyway or at the very least ask what they should bring, even if it is just a bag of crisps and a few beers when meeting someone at their place.