Paris-Stéréo was a trademark of Albert Baron. His company was located at 55, Boulevard Lefebvre in Paris. Although it also published a limited range of glass stereoviews, it’s mainly known for its paper card stereoviews with scenes of the war.
During the war, Paris-Stéréo produced 10 series of 12 paper card stereoviews in the format 8,5x17cm. After the war, the range was expanded to 20 series. The stereoviews were packed in purple boxes. The stereoviews and catalog that were published during the war do not bear the name Paris-Stéréo. The post-war catalog does [1], which means that the previously published views can be linked to the company. The series are not dedicated to a specific theme or battle.
The stereoviews are technically of high quality, but because many of the images were published during the war and were subject to censorship, they are not the most interesting images. Remarkably, Paris-Stéréo had no images of the battle of Verdun.
The last found trace of the company dates from 1928 [2].


8,5x17cm paper card stereoview from series III

The catalog refers in the footer to the 20 series of war views.

45x107mm glass stereoview by Paris-Stéréo
References
- The Great War in 3D, Paris-Stéréo catalogs
- Annuaire du commerce Didot-Bottin, 1928