I don't know about these things. Why was he banned? Was the ban permanent? what bit of the linked article I read indicates he realizes he made some mistakes. Is it a good thing or bad thing that he wants to be president of the ISU in your opinion?
My understanding is Didier was banned for 3-ish years for his part of the judging scandal at the 2002 Olympics. He was the French federation president at the time, and was specifically accused by the French judge as being the one who pressured her to judge the way she did. the judge later recanted, but a number of witnesses from other countries testified to the exchange and that he was, in fact, at fault.
Although it was temporary, the whole incident questioned the ethics of all involved, and I'm not sure there was ever a sufficient resolution to the question of whether the ethics of those people (especially ones trying to run the entire ISU) were so compromised they could no longer be trusted or if it was simething that could be rehabilitated.
However, it is very interesting that France lowered the ransom on Massot right after Didier announced his campaign.