[2] At the age of thirteen, she got married in Paris to the brother-in-law of King Henry III, Philippe-Emmanuel of Lorraine, Duke of Mercœur, of whom they had only one surviving daughter.
The king, accompanied by his mistress Gabrielle d'Estrees, marched against Philippe Emmanuel, leading Marie of Luxembourg to approach d'Estrées at Angers and capitulate on behalf of her husband.
Although the king did not confiscate their lands, their submission resulted in the betrothal of Françoise, their only child to survive infancy, to César de Bourbon, the illegitimate son of Henry IV and d'Estrées.
[5] Almost ruined by the countless expenses that had allowed her husband to raise armies in the Holy League, she refused offers of reconciliation with Henry IV, and could not return to Paris until the funeral of her sister-in-law, Queen Louise of Lorraine, in 1603.
After returning to Paris, she made multiple donations to religious orders, founding the Couvent des Capucines on the Rue du Faubourg Saint-Honoré following the last wishes of her sister-in-law Queen Louise (the nuns had to be relocated when Place Vendôme was created 80 years later);[6] and the convents of the Feuillants, the Capuchins, and the Reformed Jacobins.