on duty; in service
Le policier n'était pas en service quand il a été abattu.
The police officer was off duty when he was shot.
Maintenant je suis en service.
Now I am in service.
It is in service.
Ne fume pas quand tu es en service.
Don't smoke while you're on duty.
In service?
Je ne suis pas en service, aujourd'hui.
I'm not on duty today.
Le policier est actuellement en service.
The police officer is currently on duty.
I was on duty.
John est en service aujourd'hui.
John is on duty today.