Astra was a sister brand to Motobecane. The components appear to be early 1970s boom era and typical of entry level models. I'd need a better picture to be sure, but the rear derailleur appears to be 3rd generation Huret Allvit, which was manufactured from 1969-1975. As noted by rhm, the hubs and brakes may have date codes. I don't know if this is an further dating guide or just the American importer's preference, but Motobecane didn't introduce a mixte style frame in America until 1974. Also, I've never seen the bent mixte stays used on a Motobecane.