How to come from ROISSY CHARLES DE GAULLE Airport ?
Take RER B in direction of Paris until "Gare Du Nord" station. There, take the connection with the line 4 of the metro, in direction of Porte D’Orléans and stop at Alesia station.

How to come from ORLY Airport ?
Take RER B in direction of Paris until "Denfert-Rochereau. There, take the connection with the line 4 of the metro, in direction of Porte D’Orléans and stop at Alesia station.

How to come from BEAUVAIS Airport ?
Take the airport shuttle Beauvais - Paris (you can reserve your tickets on their web site ) : it will bring you in Paris, at Porte maillot. There, take the line 1 of the métro direction Chateau de Vincennes, and stop at "Chatelet" station. There, take the connection with the line 4 of the metro, in direction of Porte D’Orléans and stop at Alesia station.

You can check at the metro map. Here is the link: metro map.