Complex sentence: A group of French students aged 15--16, from Concarneau in Brittany, were among those injured; others included three police officers who were returning from a commendation ceremony, four students from Edge Hill University in Lancashire, and the deceased American's wife.
Split into simpler sentences: A group of French students aged 15--16, from Concarneau in Brittany, were among those injured. Others included three police officers who were returning from a commendation ceremony, four students from Edge Hill University in Lancashire, and the deceased American's wife.