A 41-year-old man drove to the police station in the city of Rennes, western France told officers he had killed is ex-wife and that her body was in the boot of his car.
Police immediately searched the vehicle and found the body of the man's ex-wife curled up in the boot.
According to the local police commander Marc Guillemois the man was “calm and serein”.
“This is a very rare incident,” he added.
According to reports he strangled his ex-wife in the hall of her apartment on Tuesday with a metal cable.
He is believed to have stayed with her body for two hours before taking it to the police station, so his children would not see it.
The suspect, who is an Algerian national, was known to police for threats and violence towards his ex-wife.
The couple divorced in 2014 but he still visited her apartment to visit his children.
He has been placed in custody and faces life imprisonment.