I also have a Peugeot (a 1962) and although the bikes are the same size and same weight (22 pounds and a few ounces) they are very different machines... (the Pug is also a fixed gear).

Even with 125 psi tyres the Gran Sport rides like a dream, handles like it's on rails, and is just a trifle fast.

I rode her in today and she was back to being her glorous old self... I have also been really pleased at how well those 630:20 Avocet tyres roll and ride, even when they are running 120 / 105 psi.

My Pug will beat me up a little more if I run higher pressures as the frame is a little stiffer and tighter.