Almost the entire centre of Lyon is one way (though, thankfully, not one way in the same direction). While I was walking around this didn't bother me. In fact, I didn't really notice. But now that I am tending to cycle places, it is remarkably unhelpful. Some of the one-way roads have a contra-flow bike lane as well, but some do not. If they do, this will not always join up with a road going in the right direction so often one has to pretend to be a pedestrian with wheels for a short section of one's journey in order to cross the traffic that is going the wrong way (or, for them, the right way). It also means that successfully arriving at a destination is no guarantee of your knowing how to get back again! But I am gradually working it out, and the rivers make navigation quite easy–you can check where you are by what the nearest bridge looks like.
Learning where the nearest source of 'velo'v' bikes is is a bit like knowing the metro map off by heart, or knowing what time the last metro leaves: Very Important Information that I have never needed to know before. I have also discovered that the velo stations are never actually in the exact spot where they are marked on my colourful velo map –this is not surprising, as the french are not a map-using people, and far prefer to wander or to ask someone, if they need to find something. So clearly eyes and a pictorial memory are more useful than maps when it comes to knowing where the nearest bike might be :)