Here’s an undemanding lighthearted comedy from Switzerland loosely inspired by a real-life spying scandal in the late 1980s, when it emerged that Swiss police had amassed secret files on 900,000 people suspected of dodgy political views. (Handing out leftwing leaflets was enough to make you a target for surveillance.) It’s a movie made for a home audience, I suspect; if you’re unfamiliar with the history, some of the events here feel convoluted and hard to follow. Though anyone old enough to remember the era will recognise the high-street golfing jumpers and creased nylon slacks in a nothingy shade of “C&A greige”.

The setting is Zurich in 1989, where Viktor Schuler (Philippe Graber), a good-natured if none-too-bright detective, is ordered to go undercover at a radical lefty theatre. He shaves off his cop moustache, buys a leather jacket and volunteers his services as an extra in Twelfth Night. The trouble is that he struggles to uncover any useful intelligence. The actors turn out to be a bunch of luvvies with fuzzily vague politics. The play’s firebrand activist director is suspected of working for the Russians, but increasingly he looks like your standard issue bourgeois misogynist bully: a man who enjoys the sound of his own voice and humiliates a female actor when she refuses to perform naked.

It’s a film with plenty of shots of Schuler hiding behind doors and comically getting the wrong end of the stick. (He is disappointed to discover a Russian that the actors keep banging on about – Stanislavski – turns out not to be a Moscow intermediary.) Inevitably he begins to question the mission and even the ethics of mass surveillance. Has the theatre opened his eyes or brainwashed him? It’s a harmless enough movie for the most part, though Schuler’s relationship with the play’s leading lady – while he is undercover, deceiving her as to his identity – feels a bit iffy after the UK’s more recent “spy cops” scandal.

• Released on 4 December in cinemas.