The castle is in Troissereux, roughly 5 kilometres north of Beauvais (less than one hour from Paris. To reach the place :

By car :

From Calais or Paris, leave the A16 at the Beauvais Nord way-out n° 15. From Senlis, take the dual carriage way towards Beauvais, via Creil and Clermont.

Once reached Beauvais, immediately follow the Abbeville, le Tréport sign.  In Troissereux (7 kilometres), turn left at the traffic light, castle is 500 metres further and you'll leave your car on the side of the road outside the castle.

By train :

Take the train to Beauvais and the cab towards the castle (10 minutes, roughly).