Almost every large town and city in Switzerland has repair cafes on a regular basis…
Highly recommended if you lack the tools or know-how to fix something. You will feel better fixing your 50Fr coffee grinder rather than binning it and buying a new one, even if it takes a hour out of your Sunday 
Other alternative in Geneva but with the same “Fix it instead of throwing it” mindset.
There is a specific website allowing you to find repair shops by subject (clothes, electronics etc).
Don’t forget the small shops near your place as well, they can do magic.
I had one repair a broken strap in my backpack for CHF 10.
Salut Guillaume, have you purchased / repaired a bike in GVA?
Salut Alex,
I bought my last bike (but 1st e-bike) in Veloland Acacias not far from where I live. Before I moved, I was going to a small bikes shop near my place.
Veloland is okish from a price and service point of view. The place is definitely too big for me. “C’est l’usine”.
For my next bike, I’ll go in a smaller shop for a better client’s experience.
All shops propose bikes repairs, but I like Péclôt 13. There is this one too in Aïre. I’ve never been there but it’s always full of people waiting with their bike. They offer repair and auto repair.
Try to find one near your place.
I don’t think they do repairs for the general public, but for buying cheap second hand bikes there’s also la fourrière (they repair and resell unclaimed bikes seized by the police)
In Bern there are “Velostationen” from the city. They repair your bike for quite a reasonable price.
You can also buy fixed up bikes: Occasionsvelo — Velostation Bern
(Plus, the stations let you pump tyres for free. The people working there are also quite willing to give you some pointers to repair small stuff yourself.)
I volunteer in a bi-annual Repair Café and it’s a great feeling. In our last event we had the following results:
Lack of parts, planned obsolescence, etc but slowly a lot of associations are putting more pressure to change the legislation in Europe.
I was very much a fan of the concept, and I participated once or twice in volunteering. However, it was not very much helpful nor satisfying, because basically any appliance with more than 12V requires a special certification e.g. electrician diploma.
I was sitting next to someone, handing a screwdriver every now and then and that was basically my contribution 
(This was in ZH)