He was among the garrison of Mayence when this place was besieged by the Prussians, and obliged to capitulate after a long and famous siege (from 6th April 1793 to 22nd July 1793).

[A] During the siege he wrote a journal of all the operations.
Unfortunately, this journal is very short, and purely military.

It has been handed down to us, and is found in the Bibliotheque Nationale of Paris in the 'Papiers de Merlin de Thionville', n.acq.fr.

Nos.
244-252, 8 vol.in-8 deg..

Beaupuy's journal is in the 3rd volume, fol.
213-228.
...
In the Vendean war, the "Mayencais," or soldiers returned from Mayence, made themselves conspicuous, and bore almost all the brunt of the campaign.