PARIS — Marianne Faithfull is in higher spirits than you might think. “On the whole, I’ve been pretty happy for years,” Faithfull muses over a glass of Coke Zero at the trendy Hôtel Costes in Paris.

The lawsuit was settled out of court, prompting reforms within the organization. She went to Los Angeles in 1979 with Sly Fox starring George C. Scott and never left, adding television, stage and ...