PARIS (Reuters) - French police stepped up controls in Paris over the weekend to ensure residents were complying with strict lockdown rules imposed to curb the spread of COVID-19, amid signs that some people were breaching them.Prime Minister Jean Castex has said people are not abiding by the rules as strictly as during the first lockdown back in the spring. Police had to break up an illegal party hosting up to 400 people at Joinville-Le-Pont near Paris early on Saturday. Under the lockdown, in force since the end of October, people must stay indoors apart from trips to buy food or other essential goods, or for a brief hour of exercise. They must also carry signed documents to justify why they are outside.