A fire during the night in an apartment building in the southern French city of Nice claimed the lives of seven people, including three young children, Mayor Christian Estrosi posted on Facebook on Thursday morning. One of the residents was also critically injured, he wrote, adding that the city has set up a crisis support system for the residents. French Interior Minister Gérald Darmanin said that the swift response of the rescue teams had prevented further casualties. The fire broke out around 4 am (0200 GMT) in a high-rise district on the outskirts of the city and raged with great intensity…