I picked up a 1984 P8 I believe in March. I was planning on converting it to a fixed gear beater, until I discovered the French headset and I believe what is a Swiss BB. Couldn't even just swap out chainrings because the BCD of the Nervar crankset is an odd 122mm I believe >_> A defining mark of the Swiss BB is a ring along the circumference of the cup:

(courtesy of http://cyclespeugeot.com/Threading.html)

My bike matched most of the components here: http://cyclespeugeot.com/images/1984...H10L_P8_P6.jpg

I said to hell with it and just found another frame ('81 Schwinn Super Sport) to fulfill my fixie pleasures.