This is an original engraving by I S Klauber.  The original painter was Joseph Duplessis.  It has been museum mounted and cleaned. The man in the painting is Gabriel Allegrain(1710-1795), a famous sculptor.

Duplessis was a French painter who studied with Subleyras in Rome 1745-49.  Returning to France he pursued a career as portraitist in Paris, while retaining close links to his home town of Carpentras.  After 1774 Duplessis won favour at the court of the new king, Louis XVI, and painted portraits of the entire royal family, as well as of Gluck (1775, Vienna) and Benjamin Franklin (1779).  While in Paris, he dispatched altar paintings to the cathedral of Carpentras, as well as decorative landscape paintings to the local hospital.  He retired to Carpentras from 1792 to 1796.

TRANSLATED TEXT FROM FRENCH:
Lower Left: Paints by Duplessis for his reception, 1774

Lower Right:  And engraves by I S Klauber for itself reception to the Paris academy 1787

Bottom Center(Title): Christian-Gabriel Allegrain

Measurements:

• OUTSIDE:  20" wide x 26" tall
• INSIDE: 11.5" wide x 15.5" tall