Traffic was brought to a standstill across large parts of France Thursday as taxi drivers parked their cars and took to the picket lines to protest Uber, an internet-based car-hire service they say competes unfairly with their business. Much of the work stoppage was focused on Paris, where strikers lit fires along the ring road and refused to provide service at the city's two main airports and train stations. According to some accounts, streets leading to the facilities were blocked. Unprepared travelers could be seen starting off on long hikes to their final destinations as they reached a France with no cabs on offer. The tense atmosphere prompted the government to issue a general call for peace, especially after a series of recent altercations between taxi drivers and private car owners participating in Uber. French President Francois Hollande later joined in the criticism of Uber, arguing that the company "respects no rule." "I understand that there are manifestations ... I can understand that there is exasperation," he said in Brussels, where he was attending a European Union summit. But he denounced the acts of aggression. "The violence is unsupportable not only for the victims, but unsupportable also for the image of our country," Hollande said. The focus of the protesters' anger is Uber's UberPop service, which allows private drivers to earn money by offering rides in their vehicles. One complaint by the taxi companies is that the private drivers are not licensed. "For two years, the government has said it wants to do something. They're doing nothing," one enraged taxi driver told the BFMTV broadcaster. The government has said multiple times that such car-hire services are illegal. However, Uber recently announced plans to expand its service into three more French cities, noting that the matter is still before the courts with no verdict expected before September. Taxi drivers say they hope their open-ended strike, which affects the whole country, will force the government to take action.