A UK Foreign Office spokesman accuses Russia of an "aggressive and co-ordinated campaign of harassment against British diplomats".
Intelligence experts believe south-west France's proximity to defence and aerospace sites makes it a target for espionage.
A couple who stayed in Shenzhen discovered their intimate moments were filmed as spy-cam porn.
Egisto Ott, 63, denies charges of handing over information to Russian agents.
Moscow has accused the unidentified man of being an undercover spy working at the British embassy in the Russian capital.
The double agent compromised more than 100 operations and betrayed more than 30 agents spying for the West.
Sciences Po Saint-Germain near Paris trains current French secret agents and potential new recruits.
The firm’s chief security officer said North Koreans tried to apply for remote working IT jobs using stolen or fake identities.
The new head of Britain's overseas spy agency has warned about an interlocking web of security challenges.
