As comedies about Hitler, the Holocaust and Nazis hiding out in South America go, “My Neighbor Adolf” is no “Mr. Kaplan.” One of the last films to star the late Udo Kier, it’s a curious, gentle and downbeat tale about old men, the lost world of pre-war European Jewry and the seemingly futile hope for justice or simple closure after surviving when so many others did not.

Kier, who played Adolf Hitler in the recent “Hunters” TV series, and “Sid & Nancy” veteran David Hayman give soulful, subtle performances that often undercut the comic intent of this Israeli-Polish production.

And after decades of thrillers like “Marathon Man,” “The Boys from Brazil,” “Apt Pupil,” “The Secrets we Keep,” “Remember” and “The German Doctor,” getting a “comedy” out of this subject is always going to be tricky.

A brief prologue set in 1930s “Eastern Europe” (Poland) shows Polish chess champion Marek Polsky (Hayman) grousing through a summer day with his extended family at their summer home. He and his wife fuss over their rosebushes, a daughter readies a camera and parents, grandparents and children pose for a family photo.

In a flash, that world was destroyed.

The year 1960 finds Marek a sullen loner liv

ing in a weathered house on the outskirts of town in “South America” (Colombia), an old embittered man rarely moved to change out of his pajamas, still obsessing over his black roses, but closed-off from the world. Making inquiries about the house for sale next door to him is futile.

But the German lawyer (Olivia Silhavy) is persistent and and pushy. And next thing Marek knows, the house next door is being tidied up and moved into. The mysterious bearded man “who wears his sunglasses at night” arrives, with his Alsatian dog Wolfie, after dark.

Something about “Mr. Herzog” seems familiar. It’s the eyes. With newspapers trumpeting the Israeli kidnapping of Nazi war criminal Adolf Eichmann from Argentina, Marek starts to convince himself that the other infamous “Adolf” of that era is living alone with his dog in the house right next door.

I mean, he’s German. The guy paints. He’s left-handed. He has a short temper and is utterly intolerant of smokers. He’s got those piercing grey-blue eyes. And, you know, he PAINTS. Who else could he be?

Efforts to interest the local Israeli embassy’s security officer (Kinerey Peled) come to naught.

“Your neighbor is not Hitler because Hitler is DEAD!”

“Bloody amateurs” Marek barks (in Yiddish, then English). “Bloody amateur!” is what he mutters at the neighbor who sets up his chess board outdoors.

If Marek is going to “prove” and get evidence and convince Mossad agents to take action against “Mr. Herzog,” he’ll need to study up. A bookstore visit to stock up on Nazi and Hitler books earns a smirk from the clerk. Buying a Minolta camera, a tripod and big lens should help — if he can figure out the tripod.

The bloody amateur” Nazi hunter underlines every trait he reads that Hitler had that Herzog seems to share. He ticks off the boxes and snaps surreptitious photos.

But to get really close to his quarry, he’ll have to dial down the feud that begins over the unruly, roaming dog, his prized black rose bush and includes property line issues.

A little chess? Borrow some coffee? The two lonely old men play, with “Herzog” knocking over the board when he loses and brushing off compliments about his painting “hobby.”

“I started when I was very young, but I guess I was better at…other things.”

The script that director Leon Prudovsky — he did the Israeli comedy “Five Hours from Paris” — and Dmitry Molinsky serve up is long on charm and almost amusing pregnant pauses. But Kier’s cagey performance doesn’t allow for anything broad and laughable. Hayman’s grousing and fumbling efforts at espionage (breaking and entering) come right up to the edge of funny.

The picture simply isn’t pitched in a light enough tone to work as comedy, and the “mystery” isn’t mysterious enough to come off either. A reach for “shared humanity” rings hollow.

Stoll, it’s rewarding seeing these two paired-up in “My Neighbor Adolf,” even if most of their scenes together leave us wanting more.

Rating: unrated, nudity, toilet trips and profanity

Cast: David Hayman, Udo Kier, Olivia Silhavy and Kinerey Peled.

Credits: Directed by Leon Prudovsky, scripted by Dmitry Molinsky and Leon Prudovsky. A Cohen Media Group release.

Running time: 1:36