Lefaucheux or Collath action of some type, possilby a Treff action(is "D.R.G.M. & Treff" atop the frame?). May have a grip safety. Immanuel Meffert had the trademark "Hubertus". Take some pics of the flats and post them especially the area from the flats to the forend lug.

Kind Regards,

Raimey
rse