Mystery Aero frame seat tube dent

[Canuk]

This is a bit of a weird one. It's got a semi curved seat tube, with a dent in it to allow the wheel forward. It's definitely French.

I can't quite work out whether it's a professionally made frame, with a bad paint job, or an amateur modification.

It's for cheap, 70 quid. The owner says it's Columbus, so I'm tempted. Any ideas?

 

[Nob]

Looks abit crude……

 

[Rod_Saetan]

Hmmm, could be made of Bondo, looks odd. Mecacycle and Geliano did this dented thing, but the general construction doesn't tie in with them, though Geliano did fillet braze a bit it seems. This looks TIG'd or brazed but not filed?