The Extinction Rebellion (XR) had said on its website that it planned to block a major Parisian location to disrupt the electoral cycle and its "business as usual" attitude.
While the cost of living is the top election theme, energy policies are closely linked to that, and incumbent Emmanuel Macron and his far-right challenger Marine Le Pen have put forward very different policies on the renewables sector in particular.
"We are blocking this Paris square to rebel against alternatives that we don't have. This election leaves us with no choice between a far-right candidate with repugnant ideas ... and a candidate who during five years cast the ecology issue aside and lied," Lou, 26, a history teacher, who joined the Extinction Rebellion movement two years ago told Reuters.
Hundreds of people gathered in Paris' 9th district brandishing banners targeting the candidates, chanting slogans such as "their inaction leads to our rebellion", or lay on the floor in protest.
Just eight days ahead of a runoff that will determine who will lead the European Union's second-largest economy for the next five years, polls show the centrist president is slightly ahead of his far-right rival, but the contest promises to be tight.