Earnest to a fault, this biopic of Dietrich Bonhoeffer, a German Lutheran pastor who resisted the Nazis and was eventually murdered by them in a concentration camp mere weeks before Adolf Hitler’s suicide, is old-school moviemaking of the sort that would have been up for Oscars 10 years ago. (Well, maybe. It would perhaps have needed a starrier cast; the actors here are solid stalwarts of German cinema, of the sort that Hollywood largely remains unenthusiastic about.)

Contributing to this slight sense of the passé is the decision to have everyone speak English but in a German accent, a curious choice that was standard practice for years but is now largely avoided. In a film aspiring to moral seriousness, it strikes a slightly odd note. It’s hard to take a line like, “I can see you standing here with a grass stain on your new lederhosen,” quite as seriously as perhaps the film-makers would like.

The film takes some liberties with the truth, which has caused a flurry of controversy among groups more au fait with the details of Bonhoeffer’s life than your average viewer. Giving the facts a bit of added dazzle is pretty much expected and not necessarily a problem, but when your subject is primarily remembered for their pacifist beliefs and theological writings, it does feel faintly counterintuitive to have them participate in various pieces of active dissent (plots with bombs and so on) – a narrative bolstering that risks missing the point of why they are of interest in the first place.

As a thriller, this is not really thrilling enough. And as a biopic, it’s not necessarily representative of the spirit of the man. But it’s solid enough film-making in a traditional no-frills mode that will always find an audience – even if it’s not particularly trendy.

• Bonhoeffer is in UK and Irish cinemas from 7 March.