Jacques I, Prince of Monaco

Jacques Goÿon, Count of Matignon ("Jacques François Léonor"; 21 November 1689 – 23 April 1751) was Count of Thorigny and Matignon. He was also the Prince of Monaco as Jacques I after his marriage to Princess Louis Hippolyte of Monaco. He also built the Hôtel Matignon.
Life.
Jacques was born in Normandy. His father was the Count of Matignon. Jacques became the Count of Matignon in 1675 when his father died. Jacques married Princess Louise Hippolyte Grimaldi of Monaco.
Issue.
The children of the couple were technically given the surname of "Goyon" after their father however they were sometimes also known under the surname of Grimaldi too. 
Name and title.
Jacques was baptised with the names "Jacques François Léonor". Using the name Jacques, his surname was Goyon. His title was "Comte de Matignon". This is French for "Count of Matignon". Therefore the mixture of Goyon and Matignon is unnecessary, and incorrect.