Castle Amber (Château d'Amberville) (1981)

From the front cover:

Trapped in the mysterious Castle Amber, you find yourself cut off from the world you know. The castle is fraught with peril. Members of the strange Amber family, some insane, some merely deadly, lurk around every corner. Somewhere in the castle is the key to your escape, but can you survive long enough to find it?

Additional materials for use with Castle Amber:

Mark of Amber is a tribute to Castle Amber set 30 years later. It is designed for use the AD&D 2e rules.

Classic Modules Today X2: Castle Amber is a conversion guide for using this module with D&D 5e rules.

Castle Amber is an expansion and conversion guide for D&D 5e.

Realistic Maps: Castle Amber provides a set of maps intended for use with virtual-tabletops.

Thorfinn Tait's website has color maps of Old Averoigne in the old Mystara maps style. There are two maps available, one at 8 miles per hex and another at 12 miles per hex.