The connection shown on your ticket is not free time. Subtract deplaning, border control when applicable, baggage, terminal movement and the time you want to be back before departure.
Short layover: stay near the connection
CDG is large. For a short connection, protecting the onward flight is usually more useful than attempting a rushed city visit.
Long layover: evaluate rail and road
RER B links CDG with Paris. Compare the current rail situation with road conditions and your terminal location before deciding whether to leave.
Set a hard turnaround point
Choose the latest time you will leave central Paris before you depart the airport. That return plan must still include terminal navigation, security and any border process.
Separate tickets change the risk
Self-transfers can add baggage collection and a second check-in. Use a much larger margin if the airlines are not protecting the connection.
Frequently asked questions
Can I visit Paris during a CDG layover?
It can be realistic on a long layover, but only after subtracting airport processes, city travel in both directions and a comfortable return buffer.
Is RER B the only option?
No. Taxis, buses, coaches and private transfers also operate; compare the live situation.
What if I change terminals?
Include the terminal transfer before deciding how much time is genuinely free.
Sources and verification
Time-sensitive airport, airline, visa, security and transport details should always be confirmed with the relevant official source before travel.