The microscope-model is a slight modification of the Small Drum Stand by Georges Oberhäuser and is offered until 1894 and discontinued in 1897. In the French pricelist of 1872 this stand is offered as:

" Microscope d'hospice compose d'un seul système N. 7. et d'un oculaire N.3, donnant un grossissement de 300 fois, avec une douzaine de lames de verre, une douzaine de verres minces, presselle, scalpel et aiguilles à dissection … 75 Francs "

Compared with this description the microscope is complete (missing only the 12 slides and 12 cover-glasses as well as the tweezers and scalpel) and has an additional eyepiece.The workshop signed in this manner during 1870 to 1873. Due to the Prussian-French war 1870/71 Hartnack had to leave Paris and put his friend and business-partner Adam Prazmowski in charge of the company in Paris. In 1872 Hartnack opened another workshop in Potsdam but until the one Paris was sold to Prazmowski in 1878 both factories numbered the microscopes accordingly.