Yes, Lemania/Nouvelle Lemania is Manufactre Breguet, according to Mr. Nicholas G. Hayek (who founded Swatch/Swatch Group and saved Swiss watch ass, to put it tres joliement, c'est simpa, oui), and MB, as well as Montres Breguet (and Omega, and Tissot, and... look up www.swatchgroup.com) belong to the Swatch Group (just like Tag Heuer, Ebel, and others, belong to LVMH - Louis Vuitton Moet Hennesey, look them up, Tiger Woods wears a Tag Heuer, etc.). Seems there are not many independent watch manufacturers these days, but you'll find 'em here in purists/watchprosite land.
Breguet rocks! Abraham-Louis would be proud as to what Mr. Hayek has done with the famous brand. Omega rocks, too, they are the flagship brand of Swatch. What makes a watch movement "in-house"? The watch brand owns the movement manufacturer's 'house', that's what. Judge by performance, cost, and reputation, etc. Frederic Piguet and ETA-Valjoux (also owned by Swatch Group) make very good movements, and the Lemania you have in your Breguet reminds me of the caliber 321 (and a bit like the 861) in the Omega Speedmaster, aka, la montre de la lune (the moonwatch).
Then there's the Dark Side ("Luke, you don't know the power of the Dark Side!"), aka, Rolex. Yippee.
Enjoy! =:^D