Hide the Monets, Manets and Mattisses -- Justin Bieber's at the Louvre!

We can't believe there's anyone on the planet that could be more immature than Justin Bieber -- but then we saw these pics of the Biebs and his proud papa, good old Jeremy Bieber, goofing off in Paris ... and remembered there's at least one man who puts the "Boyfriend" singer's childish antics to shame -- and that's his dad. These two are cut from the same cloth!

The gruesome twosome headed to the famous Parisian museum and took some wacky pics on Thursday night. Jeremy, who seemed to be really jazzed about his miniature Eiffel Tower statue, really classed up the joint with his outfit, while the Biebs looked sleek and stylish in his all-black ensemble and crustache.

In our heads, the father/son chat about heading to the museum went something like this:

Justin: "Hey Pops, we gotta enjoy being in the City of Love. Should we see some art and sh*t, or should we just go drink some sizzurp with some ratchet honeys?"
Jeremy: "Baby Biebs, I gotta mad plan: Let's go see some art and sh*t and then get our sizzurp on with some ratchet honeys."
Justin: "I like the way you think, Big Papa B. But maybe you should change out of those sweatpants? The Louvre is nice and it's Fashion Week.
Jeremy: "Kewl. I'll go put on my fancy sweats."
Justin: "I'll grab the laser pointer, but don't forget your tiny Eiffel Tower. I love it 'cause it's sooo tiny."
Jeremy: "Exactly."

And then in our heads, they do a double-cup toast to drinking the night away in gay Paris.

Also, the Louvre isn't open at night ... so they just visited the OUTSIDE of the Louvre? CLASS ACTS!