Mercier rescue proyect! Is this worth it?

I found this Mercier frame abandon in the middle of the street, the serial number, 057265, any idea of what model year is? 73 maybe ? is not my size but I feel it could be a cool project to take on, this will be my first time doing something like this. what do you guys think about it it is worth as a learning expirience? planning to build a bike for a friend after is done…. Or is in too bad condition and is more rust than metal?

I guess it use a french BB, what else should know before I open this can of worms? Thank you for the knowledege guys!!