In reply to Lew13:
We used to doss in the Helbronner station next door. Not sure if thats possible nowadays, depends on how stealthy you are, I guess.
Once, when the border post there was policed by the CRS (French riot control police with a reputation), we were settling down for the night when we were instructed to follow a monster officer ( who would make Brian Blessed look puny).
We expected to be locked up for the night (at least).
Instead the table was set with the best pasta bake I have ever eaten plus about four other courses and wine.
The mattress and down quilt were OK too.
It was a shame to have an alpine start the next day.