Generally I found Paris to be a very bicycle friendly city. However, the (probably) biggest road in Paris, the Avenue des Champs-Élysées is still invested by cars. They are loud, stinky and the come in large numbers. I walked along the whole 2 km stretch, from the Place de la Concorde to the Place Charles de Gaulle (with the famous Arc de Triomphe).
The sidewalks were crowded, and I did not see a bike path or anything of that sort. Apparently the Champs-Élysées is famous for it's cafés and shops. I don't see how anyone could enjoy a coffee outside at a stressful street like this though. There must be times when the traffic is not so bad.
I saw very few cyclists who dared to cycle in the heavy traffic. I bet it's not very enjoyable. The only time when the Champs-Élysées is in the hand of cyclists is at the final of the Tour de France.
Finally I reached the end of the Champs-Élysées. I alone because along the way I lost my Japanese companion. To get to the Arc de Triomphe as a pedestrian, one has to use an underpass to avoid the huge motorised roundabout. Pretty grim.
So at the end, one stands on this island surrounded by cars and no way to go.
A young fellow on a Vélib' -- after taking some advice from policemen -- dissapeared in the pool of cars encircling the arc. After all, it can't be that bad. Probably just takes some getting used to in order to comfortably cycle on the Champs-Élysées and about?