Peugeot rear brake location
Yes, on my 1975 Peugeot UO18, the brakes are located on the intermediate stays and the seat stays are used for the rack mount. 

The brake configuration is visible here. 


(photo source: http://oldtenspeedgallery.com/owner-submitted/joans-1975-peugeot-mixte-uo-18/#.VWFRtmDDz88)