Obviously there were many who opposed it. But how many were willing to go along? Why where they so willing?
Oooh something I (hopefully) can answer!
TL;DR Collaboration was viewed through the lens of balance of power theory (survival of the national state) and domestic political competition.
Despite assumptions to the contrary, there was little (initial) resistance to the Vichy government. Though Charles de Gaulle called for French civilians to resist, and there was an eventual insurgency of sorts (which increased as liberation approached), the general population was largely unified in collaboration with the German occupation for several years.
One of the reasons for collaboration on the part of the Pétain government was the relative balance of power at the time: the most effective strategy for the survival of the French state was to bandwagon with Germany, given that at the time, there was a high probability that Germany would dominate Western Europe. The armistice terms would allow France to continue to exist as a nominally independent, sovereign state.
Additionally, the French right viewed collaboration with Germany as a way back to political dominance after the gains by left-wing/socialist parties in the interwar years. See the fact that most Vichy regime leaders were predominantly "conservative military officers, traditionalist 'notables' and activists of the interwar Right" while the majority of the initial resistance members were associated with the Parti Communiste Français (PCF), a pro-Soviet and ideologically internationalist party.
I hope this answers your question! Please correct any mistakes; I'm just a humble student.
Sources:
Edit: my second source deals with the more governmental aspects of the Vichy collaboration. The first paragraph and source should be more relevant to the question; I got a bit carried away Edit2: spelling