He was landlord to Robespierre.
On the evening of 17 July, after the Champ de Mars massacre, the authorities ordered numerous arrests.
Robespierre, who attended the Jacobin club, did not dare to go back to the rue Saintonge where he lodged, and so asked Laurent Lecointre if he knew a patriot near the Tuileries who could put him up for the night.
Lecointre suggested Duplay's house and took him there.
The men in the family (Maurice, his son and nephew) were all actively involved in official duties thanks to Robespierre's patronage.In September 1792 his younger sister and brother joined him and lived in the front house, but Charlotte insisted moving to 5 Rue St Florentin because of his increased prestige and her tensions with Madame Duplay.
Augustin moved out from the Duplays when he was send on mission to the Midi in August 1793.