The man has so far remained unidentified and is is not clear if the violence was terror-related.
Trappes has a population of around 30,000 and is part of the far suburbs of the greater Paris area.
Only a short drive from the wealthy area of Versailles, home to the world-famous Versailles Palace, the town is known for problems linked to poverty, gangs and hardline interpretations of Islam.
It has a large Muslim population and about 50 locals are suspected of having left France to fight for the Islamic State group in Syria and Iraq, according to French security sources.
It follows a series of knife and gun attacks carried out by Islamic State and al-Qaeda operatives in France, dating back to early 2015.
France remains on a state of high terrorist alert, with police and army patrols patrolling the streets of major cities such as Paris.