This is, without a doubt, one of the funniest of all the many Polo and Andre comedies. I saw it two or three times on late night television in the sixties and early seventies. It has since dropped clean out of sight. So far, I have been unable to track down a copy on video. But I do have vivid memories of this film as well as this extremely rare original lobby card.
The story begins soon after the original Adventuress, who had been traveling with Polo and Andre, leaves them for her new married life. Polo and Andre travel back to Budapest where they take up with a new Adventuress named Svetlana Wattavich. The association lasts six weeks, during which the trio pulls off a few successful scams, with things finally going awry. As a result, Polo and Andre spend three months in jail. Svetlana, a bit luckier than our two heroes, narrowly manages to avoid conviction. But this brings their association to a complete and abrupt end. They hear nothing more from her until eighteen months later when there is a knock on the door of Polo and Andre's London hotel suite.
Polo answers the door, but sees no one. Then he looks down and sees a baby left in a basket. Excitedly, he brings it inside and shows Andre. There is a note in the basket that reads: "You are the father of this baby. I have been taking care of her all these months, but now need some time to put my life in order. Since you are the father, I feel it is your responsibility to take care of her until I contact you in a few weeks. Svetlana."
But the note does not say who the father is! Is it Polo or Andre?! This is where the fun really starts. Polo and Andre are each certain the other is the one she must be referring to. Now begins a series of accusations and denials.

Here is a typical exchange:
Andre: Tell me, Ducky, during the times you were alone with Svetlana, did anything... happen that might explain this situation?
Polo: Oh Andre! Surely you're not suggesting that I am the one responsible!
Andre: Would you mind answering the question? As I recall, we were both fairly close to Svetlana during those six weeks we worked together.
Polo: But I was very careful!
Andre: And so was I. But something went wrong somewhere. And I would wager I was probably a bit more careful than you were.
Polo: This is not fair! Why am I always the one to take the blame for everything?! You spent much more time alone with Svetlana than I did!

Still, Polo and Andre are stuck in the situation, and try to make the best of it. Of course, the task of the daily care of the baby ends up with Polo doing almost all of the work. Whenever the baby cries, Andre's reaction is to say, "Polo, do something!" And Polo always does. As a result, he grows fonder and fonder of the baby, and she of him. But he is still quite sure she must be Andre's.
Andre tries to maintain an emotional distance from the baby. But this gets harder and harder for him, even though he is sure it must be Polo's daughter. It seems that for some reason the baby finds his attempts at aloofness, as well as his Prussian military bearing, to be the ultimate amusement. Every time she sees Andre enter the room, her face lights up, she laughs, and claps her hands in joy. This has Andre totally perplexed.

Polo: Look at how the baby loves seeing you, Andre. It's as if she knows something about you!
Andre: Stop this line of talk immediately!
Polo: I've been thinking, Andre...
Andre: Oh no! Now I've really got cause to worry!
Polo: We don't even know her name. I'd like to call her Andrea!
Andre: You do, and I'll rip your tonsils out!
Polo: But Andrea is such a pretty name! And she is such a pretty baby. Look at her big eyes, and her sweet little round face.
Andre: Hmmm... I think you've got something there, Ducky!
Polo: You do?
Andre: Yes! That's a very good description of you, when you think of it. Yes, I'd say she looks quite a bit like you. Perhaps Polonia would be a better choice for a name.
Polo: Oh Andre, you can't be serious!
Polo picks up the baby who starts to playfully slap him in the head.
Polo: You may think she looks like me, but she sure acts like you!
Andre: Auugghh! I can't take any more of this! I'm getting out of here! I need a drink!

Later on, Polo tries an experiment. In an attempt to try to envision whom the baby really looks most like, he draws a scar on her forehead with an eyebrow pencil, and places Andre's monocle in her eye. The baby is thrilled with this new game, and is laughing happily when Andre enters the room. He stops dead in his tracks, glares at Polo, and says through gritted teeth, "I suppose you think this is very funny!"
The first two thirds of the film is filled with hilarious stuff like this. I have read that the scene where Andre is left alone with the baby, and has to change a diaper, had audiences of the day laughing their heads off!
Andre eventually proves to have no immunity to the baby's charms. There is a funny scene in which he comes home with a gift for the baby - a toy soldier!

Polo: Oh, how nice! You bought a toy for the baby!
Andre: Well... uh... ahem... I just happened to be passing by a shop, and they had these on sale... So I thought...

At this point, a clever little in-joke is worked into the script. The camera zooms in on the soldier, which turns out to be a replica of Erich von Stroheim as Lt. von Steuben, the character he played in "Blind Husbands". Of course the baby is thrilled with the toy, and is rarely without it for the rest of the movie.

The movie then becomes very exciting and suspenseful towards the end, when Polo and Andre finally learn that this is not Svetlana's baby at all. It seems she has taken up with a gang of kidnappers. It turns out this was all an attempt to hide a kidnapped baby out until the heat dies down. While this lets Polo and Andre off the hook paternally, they then find themselves having to outwit the gang in order to return the baby to her worried parents. It ends with the kidnapping gang in the hands of the police, and Polo and Andre lauded as heroes. The baby is finally back with her loving parents who are grateful to our two heroes for all of their help, and the fine care they've given their daughter during her time in their custody.
The final scene shows Polo and Andre reflecting on their experience.

Polo: You know, Andre, I really enjoyed being a papa. I've decided I'm going to get married some day, and have lots and lots of babies!
Andre: An admirable goal, Ducky. But do you suppose the world will ever be ready for it?
Polo: Why, Andre! What do you mean?
Andre: Oh... nothing!

-The End-

This was an extremely popular, successful entry in the Polo and Andre series of films.  I am still hopeful that one day it will be re-released for a new generation of movie fans to enjoy.