The suit was filed in Potter county Monday.
It alleges Marsh III engaged in sexual activity with a "then" 16-year old boy beginning in 2010.
The plaintiff alleges Marsh paid the young man cash in return for the sexual liaisons in 20 different sessions.
The sessions allegedly took place in Marsh's office in the Chase building and at least once at Marsh's home at Toad Hall.
The suit also names Marsh's wife Wendy, associate David Weir, Stanley Marsh IV and McCartt and Associates among others as defendants.