The Monobloc and its simplified or "S" version, had a long career: from 1912 to 1937, manufactured and sold under at least four brand names: Boucher, Liebe (and Boucher & Liebe), Jeanneret, Broutin. The exact timing of these brands is somewhat obscure. Liebe is attested in 1912 (4 rue Hautefeuille, Paris), Jeanneret & Co. in 1922 (31 Bd St Germain, Paris), other intercalated in an uncertain order ...

On a manual undated, three formats are available: 6 x 13, 9 x 13 and 4.5 x 10.7 cm.
We have here a "Monobloc Simplifié", of which there are at least two versions: one with air brakes visible as here, and the other, probably older, which has not.

This specimen must date from 1927 or 1928, as it appears with the choice of lens from the Photo-Plait catalog dated 1928, and the numbers of the Saphir Boyer which date them between 1925 and 1930 (No. 35867 and No. 35921).

Compared to the Monobloc, the simplified version no longer has focusing, and loses the panoramic function.

The shutter Decaux with air brake allows speeds between 1 second and 1/100, and the1/300 if separating the cylinder rod from the movable pin connecting the inner mechanism. Not necessarily practical, but effective! The bulb is obtained by triggering in two stages, the brake being set to "0".
A wreath on the side of it has the numbers from 0 to 6, corresponding to (about as stated in the manual):

  0 = 1 s
  1 = 1 / 2 s
  2 = 1 / 4 s
  3 = 1/10 s
  4 = 1/25 s
  5 = 1/50 s
  6 = 1/100 s

The principle of the air brake is simple: the numbered ring is pressed onto the end of the cylinder by means of a spring held by a screw. A hole of about 1.5 mm let allows air inlet. The face in contact with the cylinder has a circular groove the end of which corresponds to the hole, becoming wider and deeper. The contact face of the cylinder itself is drilled with a hole: as the hole is opposite to a more or less wide portion of the groove, the amount of air that can enter the interior of the cylinder varies. The piston slides inside thus move faster or slower. It was enough to cut a piece of fresh leather for this almost centenary mechanism to rework like new.

The inner portion of the shutter is also special; metal plates overlap. Upon triggering, they move away from each other, and then back overlap. It's almost a focal plane shutter, but instead of moving in the same direction, they oppose. Such a principle used with a modern, highly sensitive film undoubtedly would produce some darkening of the edges ...

The folding viewfinder includes on the front a lens with a cross-mark, and behind a blue lens that supposedly provides a vision to a scene in black and white.

On top of the camera, a brass plate confirms the model: "Le Monobloc Simplifié, Brev. SGDG" On the other side, a spirit level helps to position the camera horizontally. A Congress type thread is also available on the bottom. The nameplate is located on the right side under the handle. It is written, "Jeanneret & Cie, Constructeur, 31 Bd St Germain, Paris"

The lens supporting plate allows a shift of 12 mm upwards (the leaflet tells 14 mm). The lenses, Saphir Boyer with an aperture of f: 4.5, are fixed focus. The diaphragms coupled by means of a rod, has a minimum aperture of f: 32.

The Monobloc Simplifié uses the plates magazine "Monobloc" storing 6 stereo plates, or 4 color autochrome plates. In this case, it was necessary to place a filter at the back of the lenses in the square notches provided for this purpose.