Together with the Pussy Riot punk group in Russia, Femen became part of a post-Soviet protest phenomenon that sometimes drew a violent reaction. In 2011, Femen said that Ms. Shachko and other activists had been abducted in Minsk, the capital of Belarus, after campaigning in front of the K.G.B. headquarters there. Several members were beaten up in Kiev, Ukraine’s capital, in 2013 ahead of a visit by President Vladimir V. Putin of Russia.

Ms. Shachko and several other activists from the university town of Khmelnytsky, Ukraine, founded Femen in 2008. After a few conventional protests, they decided to demonstrate topless, often with political slogans written on their bodies.

At times braving icy temperatures, Femen members protested in Ukraine against sexual exploitation; in Davos, Switzerland — the scene of an annual conference of world political and business leaders — against income inequality; and, in St. Peter’s Square at the Vatican, against policies of the Roman Catholic Church, among other targets. In their nakedness they wore flower crowns to symbolize chastity.

In 2013, members of Femen ran topless in front of Mr. Putin as he visited Germany, drawing a grin and two thumbs up from him before guards wrestled the activists to the ground.

Ms. Shachko, along with several other Femen members, moved to Paris that same year and was granted political asylum by the French authorities. She maintained that the group’s members had been pursued by Russian special services and that the agents had planted a grenade in Femen’s office in Kiev, along with a photograph of Mr. Putin.