Part of the /S, it has everything of DIN. Ciutadella is a fair alternative. Main concern would be to clearly see /S finials. Horizontal? Slightly oblique? Asymmetric? Searching more.
Better samples here and here

Simplon b+p might work pretty well, the closest I've found so far, could even be matching.

Maybe Flama?
http://www.felicianotypefoundry.com/cms/fonts/flama