By Joel Leaver Kate Moss celebrated a milestone birthday on an evening out in Paris with some of her family and pals this week. The model, now 50, marked the occasion on Tuesday whilst in France. She was joined in its capital city by her partner Nikolai von Bismarck, 37, and her daughter Lila Moss, 21, whom she shares with magazine publisher Jefferson Hack. Seemingly on their way to a party, Kate and photographer Niolai were spotted leaving the Ritz Hotel earlier tonight with some of her pals. It’s believed that they were heading to a restaurant for a gathering, which included model Lila. Kate…