Roman Polanski will appeal his arrest in Switzerland and their plans to extradite him to America.
The filmmaker was arrested on Saturday after arriving in Zurich to pick up a lifetime achievement award. He was detained over the 1977 incident, which saw Polanski flee the country after pleading guilty to having sex with a 13-year-old girl.
He has not set foot in the country since, and has been living in France - which has limited extradition with the US.
Polanski's lawyer said, "We will be demanding that he be freed. The we will fight the extradition."
Swiss Justice Minister Eveline Widmer-Schlumpf said that when Polanski arrived in the country "they had no choice from a legal point of view but to arrest him".
The French Culture Minister, Frederic Mitterrand, said he was "stunned" to hear about the arrest.