Comparison of the Safety and Efficacy of HOE901-U300 With Lantus in Children and Adolescents With Type 1 Diabetes Mellitus

Primary Objective: To compare the efficacy of a new formulation of insulin glargine (HOE901-U300) to Lantus in terms of change of HbA1c from baseline to endpoint (month 6) in children and adolescents with type 1 diabetes mellitus. . Secondary Objectives: To compare HOE901-U300 and Lantus in terms of: * Percentage of participants reaching target HbA1c and fasting plasma glucose (FPG). * To assess the safety of HOE901-U300 including analysis of events of hypoglycemia, events of hyperglycemia with ketosis, and development of anti-insulin-antibodies.