Unknown brazed steel frame
The First photo shows a Gipiemme brake bridge. This part, like the SunTour dropouts, has been selected by the frame builder but doesn't really help to identify the builder.
the tubing on the main frame has been brazed in an unusual style most often associated with Peugeot. The frame is probably not a Peugeot.
Most likely it is from a small volume custom framebuilder or possibly even a decent home or work project. Ultimately it is very unlikely that you will determine the true origin.