I emailed Cyclable about reserving bike rentals, which Rick Steves promotes in his France book (pg. 779), but they responded they do not rent to individuals. Rick needs to take them out.
You are bringing back fond memories of my renting a bike from the train station in Annecy when I was a young teenager, and riding around the lake to Talloires to visit friends of my fathers. This was back in the dark ages - no idea if they still rent bikes there.
You can forward me the email if you like, but their web site lists prices that certainly look like individual rental rates, e.g. two hours for eleven euros:
You may have found others already; a quick search turned up many others. I remember noticing several bike rental places when I was there.
That email apparently came from a national office of Cyclable, so we have re-sent the question to the Annecy office.