The minimum rate for a Paris taxi ride is 5.40€, for one to three persons. (Three passengers is the normal capacity, although the driver may allow four passengers if s/he wishes.)

Fares are higher outside of daylight hours.

You'll pay supplements from taxi ranks at train stations, for luggage, and for transporting a fourth person, if the driver agrees to do so.

Tipping is not essential, although 10% is appreciated.