PARIS — French police in riot gear used tear gas as French taxi drivers stepped up protests against US online ridesharing service UberPOP on Thursday, blocking road access to airports and train stations in Paris and other cities. Aeroports de Paris, the operator of the French capital's Charles de Gaulle (CDG) and Orly airports, warned travelers to take local train services because of the taxi protest. “Access by road is completely blocked,” the company said on its website. “The only way to get to CDG is (by train).” French media showed images of burning tires blocking part of the ring road around central Paris, as well as scuffles between protesting cabbies and other drivers, while police in riot gear at one point intervened using tear gas. Taxi drivers also blocked access to Paris' Gare du Nord train station, from where the high-speed Eurostar and Thalys services run to London and Brussels. — Reuters