Union sources said the stoppage would take effect on Monday and could last for four months.
"The COVID crisis has a negative impact on oil products demand, which causes a very sharp deterioration of refinery margins," Total said.
"In this context, the Donges refinery is operating at a loss. We have decided to halt it (...) for the months to come, awaiting better economic conditions", it added.
It said the 450-million-euro ($534 million) modernisation of the 220,000 barrel-per-day facility, in Western France, was nonetheless ongoing.
($1 = 0.8421 euros)
(Reporting by Benjamin Mallet; Writing by Benoit Van Overstraeten; Editing by Sudip Kar-Gupta and Pravin Char)