Been there ... done that.
An early-to-mid 1970s Peugeot will definitely have a French-theaded bottom bracket.
An early 1980s Peugeot will definitely have a Swiss-threaded bottom bracket, usually denoted by a gold anodized fixed cup.
If you have a late 1970s Peugeot, please let me know what you discover, because you are outside my experience and expertise.
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"Far and away the best prize that life offers is the chance to work hard at work worth doing." --Theodore Roosevelt
Capo: 1959 Modell Campagnolo, S/N 40324; 1960 Sieger (2), S/N 42624, 42597
Carlton: 1962 Franco Suisse, S/N K7911
Peugeot: 1970 UO-8, S/N 0010468
Bianchi: 1982 Campione d'Italia, S/N 1.M9914
Schwinn: 1988 Project KOM-10, S/N F804069