Hello Krister and CR Listers
There are many Listers far more experienced in Italian matters than myself, but I will stick out my neck and atate that this frame is definitely not a SOMEC, the reason being that I have never seen a Somec with long-point lugs or seat-stay caps in a wrap-over fashion. In any case SOMEC always engraved their seat-stay caps/eyes.
My take on this frame is that it is French...the lugs are either Bocama or Vitus...I ought to know but my mind.s not at its best at the moment. The seat-stay caps are very French as is the method of finishing the chainstay ends. The giveaway to my mind is the small cable eye attached to the rear drop-out...a neat idea. Bernard Carre used this extensively in the 1960s, but this frame is neither a Carre nor is it from the 1960s.
My opinion is that it is a 1980s (early) MOTOBECANE...and from the top of the range. The firm revised its designs, transfers and paint finishes at that time and produced frames in Vitus, Columbus SL and Reynolds 531 - most of them with this lug set. I have a Vitus 981 finished in metallic mid-blue, there was another model with a metallic pink finish...very sexy, and another with a greenish-gold metallic.The firm adopted B/O the small rear cable eye on these models.
The frames were made to BSA norms ( or at least those shipped into the UK were) using Imperial dimension tubes not metric. The bracket shells were obviously built without thread and then threaded according to demand. I sold quite a lot of these frames and bikes...some came with BSA thread and others with the dreaded Swiss variation on L/H - R/H. I recall buying sophisticated FAG sealed bearing brackets and dismantling them to reverse the cups...seemed to work..but that's a lot of bottom bracket cups ago.
I have not been able to open the pages with the original photos, so I have not had the benefit of the larger picture. Pity really because I remember that Motobecane also used some odd cable guides on the top-tube.
Hope that helps
Norris Lockley...Settle UK...where my powers of recall are diminishing by the day