An interesting car. It was built by "Schulz Tuning".
This is six-door limousine. Mercedes did make a 4-door W123 Limo, in which there the rear doors were lengthened. The Schulz car appears to be using center doors from a factory W123 Limo. The SEC-style hood makes it vaguely resemble a W126 Coupe.
Is it forbidden to ask the source of your image? I have found copies of this picture with the front grill emblem blacked out, or replaced with a colored circle. None include the Mercedes star, like your image.