Upvote:1
I am assuming that you have a visa for the Czech Republic, or that you are a citizen of a country whose citizens do not need a visa for short stays (for example, the United States), and that you are going for a short stay.
If this is true, you do not need a transit visa for France. France and the Czech republic have common border controls, including a common visa regime, because they both belong to the Schengen area. You will clear immigration in Paris, and your flight to Prague will have no border controls -- it will be like a domestic flight in the US.