Vigil Mass At Cathedral, Rouen France

According to the website of the Cathedrale de Notre Dame de Rouen, this is the mass schedule for Easter Saturday, April 7: SAMEDI SAINT 7 AVRIL 10h00 Cathédrale Pas de messe 18h00 St Godard Pas de messe 21h30 Cathédrale Veillée Pascale et Messe de la Résurrection du Seigneur avec baptême d'adultes pendant la veillée pascale
22h00 St Patrice Veillée Pascale et Messe (forme extraordinaire du rite romain) Hope this is of some help.

Veillée Pascale translates to Easter Vigil / Easter Watch. Messe is mass. St Patrice is another church in Rouen, not the cathedral. It looks like 9:30 pm o'clock at night is when you need to be there. The rest of the line says: .... mass of the resurrection of the lord with baptism of adults during the easter vigil.

Thanks for the info and have a Happy Easter