Leaving a French registered car in Germany

... and if I leave it parked on the street?

Probably no problem as long as it is legal to leave it parked on the street for the time period you are gone. Sometimes a car can be parked on a street only for a day or two and then it has to move.

I think I could risk that, as only away for about 5 days.
I was more worried about the police or customs objecting to there being a foreign registered car in Germany whose owner is not in the country.

Thanks MarkK

You also need to make sure that you are not driving into an area where a German environmental sticker is required (unless you somehow have one).

good point about the Umweltplakette, which would pretty much rule out many larger stations.

Sort of like driving and parking a German car near a station in Strasbourg or Paris without a Crit'Air.

I didn't think about the Umweltplakette. Do they maybe let foreign cars get by without one?

My understanding is that enforcement is stricter in Germany than it is in France for Crit'air (where there seems to be nearly no enforcement outside of pollution alert days). I am not sure about what happens in case of a violation: if it is "just" a fine it is OK I guess, but if you have to turn around it is no good!

Heidelberg or Mannheim

Thanks again MarkK!