Are you saying that the Frelon has a Sikorsky heritage?
The Frelon was the first large helicopter that the French had designed. They used the Turmo gas turbine that was initialy designed to power railway trains. They had, then, not got the wherewithall to design the gearboxs and rotor system to that scale so they bought the rotor system from Sikorsky and Fiat did the gearboxs.
Could have been a successful civil aircraft apart from the noise, appalling fuel consumption and poor cruising speed.