You can hear two examples of the French pronunciation of Maximilien here:Http://www.forvo.com/word/Maximilien/Http://www.forvo.com/word/Maximilien_robespierre/Based on that, the French pronunciation of Maximilien must be MAHKS-meel-yawn or MAHKS-mee-lyawn (also compare the pronunciation of Aurélien and Émilien, where the -ien is pronounced exactly the same).