Charles-Auguste Questel (19 September 1807 – 30 January 1888) was a French architect and teacher. As well as designing new buildings, his projects included the preservation of historical monuments. He worked on several historical monuments included in France's first list of such structures, the list of 1840.
Born in Paris, Questel was a student of Félix Duban at the École nationale supérieure des Beaux-Arts, and took a second-place Prix de Rome in 1844. He became a member of the Académie des Beaux-Arts in 1871.
Questel became the patron of his own atelier at the Ecole. Among his students were Henri Paul Nénot, Ernest Sanson, James Freret, Eugène Train and the Swiss architect Alfred Friedrich Bluntschli; he was the father-in-law of French architect Honoré Daumet.
Questel died in Paris. Upon his death the atelier was taken over by Jean-Louis Pascal.
His architectural work includes: