Marielle de Sarnez was born in the 8th arrondissement of Paris on 27 March 1951 and grew up in a family with close ties to the French political establishment. From 1961 to 1967, her Gaullist father Olivier de Sarnez, who had been in the French Resistance, was chief of staff to Roger Frey, Interior Minister, and her mother was responsible for floral arrangements at the Élysée Palace. Nevertheless de Sarnez joined the May 1968 protests while still a high school student, was kicked out of Lycée Sainte-Marie de Passy Catholic girls school and participated in the occupation of neighboring boys school Lycée Jean-Baptiste Say. (Her father was elected as a deputy to the National Assembly on the Gaullist conservative Union of Democrats for the Republic—UDR—ticket a month later.) After earning her baccalaureate from Lycée La Fontaine, de Sarnez began working in retail.