This is Call fo Cthulhu set in the Napoleonic Period!! Special rules and Equipment give the feel of the time, with horror. Maybe think Pride and Prejudice and Zombies

Reims, France, November 1830. It has been less than four months since the July Revolution took place, in
which the Bourbon King Charles X was overthrown and his more liberal cousin, Louis-Philippe of the
House of Orleans, was installed as King of the French. While Reims, in the north of France, has
not seen the same sort of riots and political violence that has rocked Paris since the summer, the effects
of the Revolution have been felt nonetheless. The uneasy political situation at this historical juncture
is elaborated in the boxes on pages 3 and 5.

In the midst of this upheaval, a pair of unusual, possibly supernatural events have occurred.

No prior experience needed. Horror themes but not strictly adult