One of the environmental movement's pioneers in Europe, she helped found the French Green Party and was a member of the European Parliament for five years.

She advocated for a wide range of issues, including nonviolence, world peace, nuclear disarmament, alternative energy, and feminism.

Upon returning, they lived in an old farmhouse in Biederthal, near the Swiss border, where they installed a solar energy system and raised their family.

She worked to preserve historic homes and assisted with the "squatting" movement to successfully protest a proposed lead factory on the Rhine River and a nearby chemical plant.

She also joined activists in opposing nuclear power plants, including one planned in Wyhl in southwestern Germany, where she camped in a protest community near the site.

In 1979, she led the Europe-Ecologie political movement for the environmental group's first European elections, which obtained 4.39 percent for a total of 888,134 votes in France.