Re: 2 important questions regarding marketing in Geneva
Post 1
1. Not legal, as pretty much anywhere in Europe. I'm pretty sure you can't get a permit either. So if you really want to have posters on the street you'll have to go through outdoor/out-of-home agencies. This is probably too expensive for you.
Alternatives - pubs, restaurants, certain shops, etc. Just go in and ask the manager if you can hang up a poster (and/or leave some brochures). Places like Clubhouse and Pickwick's have a special spot for these things. Try to identify the places that your potential audience hang out in.
2. Maison des Associations near Plainpalais (in Rue des Savoises) has different size rooms and prices are decent. The rooms are not pretty, but functional. Just walk in during office hours and ask to see a few rooms.
There are a few other places you could try (e.g. schools, town/quarter centers), but I can't help you with details.