"The signing of a security agreement between France and Ukraine could lead Russia to step up these operations in order to increase its influence, undermine the credibility of our action and weaken our national cohesion," the memo said.

On Friday, French President Emmanuel Macron and Ukraine's Volodymyr Zelensky signed a security pact calling for French military and civilian aid for Kyiv in its war against Russia.

The defence ministry's document calls for measures to "reduce vulnerability to subversive actions that could affect our personnel, infrastructure, teams or activities".

"The aim is to raise awareness of the threats of sabotage and cyberattacks that can affect staff and their families, facilities, information systems and networks," Lecornu said.

"Vigilance levels will need to be stepped up and regulations rigorously enforced to guarantee the security of our premises."

Establishments working with the French defence ministry should also take note because they "may constitute targets for Russia, in particular the defence industry network", said the memo.

Lecornu said that since Russia's invasion of Ukraine in 2022 Moscow had been conducting "hybrid interference operations" against France and its partners, and those attacks "primarily" concerned the French armed forces.

Speaking to reporters on Friday, Macron said that cyberattacks and disinformation campaigns by the Kremlin showed that "Vladimir Putin's Russia has become a systematic actor of destabilisation in the world".