Hulot doesn't want to be a candidate, he has been using his popularity to pass his ecological message by primarily blackmailing the left. The French want him as an environmental champion, but are prepared to send a message to the big parties by voting for him in the 1st run. The blackmail has worked, all main parties have signed his "ecological pact", which means that they can be hold accountable later. That managed to sink the French Greens to the 3% level, which they deserved.