Beefsteak Café de Paris

Café de Paris sauce is a butter-based sauce served with grilled beef. When it is served with the sliced portion of an entrecôte or a faux-filet (in English: a sirloin steak) the resulting dish is known as "entrecôte Café de Paris". The sauce is named after the restaurant where it was created, the Café de Paris in Geneva, Switzerland. The sauce was popularised in the 1930s by the Café de Paris restaurant in Geneva, then owned by Arthur-François (Freddy) Dumont, and entrecôte Café de Paris remains the restaurant's speciality. The Café de Paris attributes the origin of the sauce to Mr Dumont's father-in-law, Mr Boubier.

Source: Wikipedia