BRITONS have been warned: Stay away from riot-torn Paris. The Foreign Office says the French capital — which has been rocked by violent demos — is too dangerous. Protests against a new employment law have erupted into riots, with fierce fighting in the shadow of famous tourist spots like the Eiffel Tower and Notre Dame Cathedral. Cars have been set alight, shops looted and gangs of youths and masked men swinging baseball bats and wooden planks have had running battles with riot police who have used water cannon and tear gas.The Foreign Office alert is a huge blow to France,...