“Two representatives of Uber today went voluntarily to a police hearing that is part of a continuing legal proceeding—they have since been taken into custody,” an Uber spokesman said. “Uber is always willing to work with authorities to overcome possible misunderstandings.” The detentions mark a big escalation of the government’s campaign against Uber in one its major markets, following a series of taxi protests that snarled roads across France last Thursday. Uber says it has nearly one million regular customers in France, including about 400,000 who use Uberpop.