In anticipation of this inheritance, Thomas Francis and Marie did not establish themselves at his brother's ducal capital, Turin, but dwelt in Paris, where Marie enjoyed the exalted rank of a princesse du sang, being a second cousin of King Louis XIII.
The prospect of Marie's eventual succession to the Swiss principality of Neuchâtel, near Savoy, was foiled in 1643 by the king's decision to legitimate Louis Henri de Bourbon, chevalier de Soissons (1640-1703), a son of Marie's late brother.