Mourrain doesn't show up in LBK or BDT yet, but it's clear that he does lots of illustrations for childrens' books. The style we see above seems to be his most common, but he also works in a more monotone, shade-heavy approach. More of his work can be seen here.
I don't know if this little collection appears in any particular book (I couldn't find it), but in any case it appears to involve three children visiting these famous places:
Pyramid entrance to Le Louvre.
Opéra Garnier’s grand staircase, with the Phantom of the Opera just visible under the stairs. EDIT: thanks to "troglodyte_mignon" in comments for the info!
That's The Brooklyn Bridge, of course.
And finally, Le Jardin des plantes, which I understand to be headquarters of the National Museum of Natural History, which also includes a zoo! :D
Btw, I found that statue pretty cool, both in spectacle, and due to the fact that Lamarck was an early proponent of evolution. (I'd never heard of the guy)
Layout of Le Jardin, showing its four main galleries, greenhouses (it was originally a royal garden for medicinal plants), and all the smaller buildings.
I've only been to Paris once as an adult, and certainly regret not spending time here(!)
BONUS: Maybe a theme song-- https://www.youtube.com/watch?v=tN64qgptQQA
Ha, I was in the Jardin des Plantes just one hour ago!
The second image is Opéra Garnier’s grand staircase: https://cdn2.civitatis.com/francia/paris/galeria/panoramica-gran-escalera-opera-garnier.jpg
And I’m pretty sure the guy with the black cape, under the stairs, is the Phantom of the Opera.
Super, thanks!
I've added the info. ^^