A Touch of Venus - Season 1 (1968)

I remember this as having one actor only, playing a man who, whilst pacing about his flat, got progressively more depressed about his failed love life, and ended up by shooting himself, off camera, at the end.

Elegant but nervous widow Marie-Louise has retired from the world to her Paris penthouse and roof garden, but her privacy is invaded by a cheeky young electrician who appears on top of an adjacent building to mend a short circuit.

Rosemary returns from a party to the empty Hampstead house where she has lived since the death of her husband. He died of an overdose of sleeping pills - was it accidental - she tries to find out.