for people who haven't booked yet, flying to Paris isn't really an option due to prices/lack of flights so have a look at the following options:
Lille
Caen
Brussels
Nantes
Bordeaux
Marseille
and one city that probably not many considered - Milan
direct flight from Liverpool to Milan on Friday costs £48 at the moment, lands in Milan 20:15, night out/hotel in Milan, direct train at 06:25 from Milan to Paris £69.81 atm, you're in Paris at 13:12