The biggest reason was the tax cuts (which will not pay for themselves, that's nonsense like all trickle-down theory) and the complete slashing of public transit and transportation alternatives for people outside of Paris, Marseille etc.
Thanks to tax cuts and reforms, the people living in small towns and rural areas have literally no alternative, they have to use a car. So by trying to greenwash corrupt policies with a at-the-pump fuel tax, the French government would in effect be forcing a highly regressive tax on ordinary people, who are already struggling to make ends meet, while completely neglecting to deal with the highly polluting fossil fuel and transportation businesses.
It's not trickle down theory. Paris overtook London as the city with most high-net-worth individuals. Thus a lot of people are not paying taxes in Paris as opposed to London.
Though, of course, it depends how much money they end up actually paying compared to the lost revenue. But this is the one point that I can accept. The others are unacceptable, we are in agreement about them.
Even if the timing was very stupid (mixing it with a tax cut for very high income individuals to entice them to relocate to Paris from London post-Brexit, even if in the end that tax cut pays for itself), the French gov. tried to do the "right" thing, and it completely failed to communicate this. (As far as I know.)