I think I might have one page from it; the photo is of Hinault and a team-mate, riding their blue Gitanes.
You could take several scans, like 2 or even 4, and then join them together with image editing software.
Or if you have a good quality camera; take a photo with the camera on a tripod. One way is to put the poster on the floor and the camera over it. I used to do this with record and cassette covers before I got a scanner. Obviously don't used flash, and use the shutter self timer, or a cable release.
The resolution won't be as good as a scanner though. And ideally you'd want the poster to be as flat as possible, which might be a problem with eg a poster that's been rolled up.
