I would imagine that they write him a cheque for the remainder he is owed for first place, mail him a yellow jersey its accompanying torphy and input his name into the excel file listing the winners. It will also affect his standings on the UCI pro tour. This is not the way you really want to win the tour de france though, or any other sporting event. I assume they will have a little press coverage of him maybe putting on a yellow jersey to please the media, but if I was him I would do my best to avoid it.