From my dear Jemiba,
Delanne 360 :was a tandem delta wing interceptor project of 1950s,with
a new design ,twin tail fins ,and a bubble canopy.it had a single
jet engine, 2.5 mach speed and 15000 m altitude.
This is also my privileged hypothesis.Surprisingly, the DL-240 is shown in this 1947 item from Aviation to be a very different design.
Your image may show an early version of the same concept.
I found this drawing identified as Delanne 240. I do not know the source, and unfortunately, I did not find more information.
This is a possibility. However, the drawing shows a four-seat, too small for six seats.May it was DL-230 ?,but the picture shows only four seat ?,
DL-230 was a tandem wing six-seat transport monoplane project,powered by two 185 hp engines