Ihagee introduced the Exakta Model A as the first compact SLR using 127 Roll film in 1933. This is known world over. It is also commonly said abroad that in 1936 the Kine-Exakta was the world's first single lens reflex that used the now standard cine film and the 24x36 mm picture size.
-Ok....
If we can consider the Vest-pocket Exakta the forerunner of the Kine-Exakta, the Min and Gelvetta would also be the forerunner of the Sport.
The MIN, according to J.L. Princelle, was created in 1929. by A.A. Min and it produced 75 pictures of 24x 32mm size. That way, this was the first 35mm SLR, but not the first in 24x 36 size. And its shutter principle, which was also the forerunner of Sport, introduced the metal vertical focal plane shutter on all miniature cameras, and of course 35mm cameras 31 years before the reflex Konica/Copal shutter was first know. but also before the Contax rangefinder from 1932. Several large size cameras had before vertical focal plane shutters but were of fabric type.
The Gelvetta created by A.O. Gelgar was first shown at Sovietkoe Foto at January of 1935, although its series production only begun in 1936. Of course the model shown in 1935, was made in 1934 when still Exakta had only Vest pocket camera types.This was the first 24x36mm SLR.
Note that really this camera was developed in parallel with VOOMP GOI rangefinder of Leica type (S.F. October 1934)
Every detail copiled from J.L. Princelle pg 40 2nd edition.
More than that at Abramov’s site
http://www.photohistory.ru/1207248178962562.html Russia's first (and possible in world) SLR 35mm film camera, produced by Leningrad plant [GOMZ] since 1936. First SLR 35mm film camera in the world with the metal vertical shutter. The format of the frame of 24x36 mm. Low temperature resistant. Speeds 1/25, 1/50, 1/100, 1/200, 1/500 s. and
". " [Industar]-10" 3,5/50 lens with bayonet couplings. Automatic exposure counter. Rectangular superstructure with the viewfinder eyepiece located on the upper panel; direct optical viewfinder on the right side of superstructure. Film transport knob with internal speeds dial. The camera uses non standadard 35mm cassettes ,50 frames on 2m film. Removable back. Different production series have different finishes , absence or presence of shoulder strap ears. Size: 133x102x69mm, weight - 820 g. Production: about 20 thousand pieces.
According to the exposed the probability of Sport have been the first camera is great once its roots were born in 1929 when the Exakta name still did't already exist .
Regards.LP