Uh... the drawing is exactly the same, almost.
The Trait d'Union's one seems to be a manufacturer design, while Jemiba's one (at http://www.secretprojects.co.uk/forum/index.php/topic,1575.0.html thanks for the precise direction) is signed JMC, for Jean-Marie Cuny I think (author of the Docavia book), and is the same improved (by an historian) to be complete with the second half complete.
I am not an expert on the subject, I can simply translate Charles Claveau's text in the Trait d'Union #172:
Bréguet 870 and 871: “Stratospheric” aircraft (of which the Br 1011 and 1012 would have been flying scale models), the Br 870 and Br 871 should carry 60 to 80 passengers on 5,000 to 6,000km. Studied from 1944, they used 6 Arsenal 12H engines of 1,500hp, or 4 Arsenal 24H of 2,500hp, or 4 Hispano-Suiza 24Z of 2,500hp. With a span of 50.8m, they would weigh 90 to 100t at take-off.[PS. I see not a word about this 870 to be a flying boat, despite the drawing…]
Bréguet 1000 and 1001, 60 tons flying-boat : after armistice 1940, the Bréguet design bureau designed a stratospheric transport, transatlantic, monoplane of 60t, transporting 24 passengers and 8 crew members. Named Br 1000, it was powered by 6 groups of two Hispano 12Z or 12Y45 engines in tandem driving coaxial propellers. A version with only 4 groups was considered with the name Br 1001. With about the same range and weight as the Br 1000, the Br 1001 had a maximum speed decrease from 620km/h to 450. [PS. Up to here, no word about being a flying boat] With the same wing and engines as the Br 1000, the Bréguet design bureau imagined a stratospheric flying boat of 60t. This project has been soon cancelled.
Conclusion: the drawing of both 1000 and 870 seems none of them but the 60 ton flying-boat with no name, using the wing and engines of the Br 1000… Thanks Toura to have made me read that all and clarify.