I like to immerse myself in certain periods, one way I do that is by watching colorized videos of life in the old days on YouTube. I notice in pretty much all of them that the French people look the most well dressed, that their popular city’s look the most attractive and well cared for, and that they generally seem to be the most leisurely.
Does anyone know if this was considered a truism even by the people of the time? Or did everyone think whatever nation they lived in was the most leisurely?
Leisure means different things to different people, and from the description, you seem to be mostly interested in the aesthetics of leisure, about which I have no expertise at all.
But in economist-speak, leisure is "time spent not working," and by that measure, France is among the least leisurely countries in the world. According to Huberman and Minns, "The times, they are not changing," French working hours in Belle Epoque France (1880-1913) were about 3100 per year, or about 65 hours per week. This puts them near the top of the league tables in most decades, though in this period all developed countries have staggeringly high working hours compared with the late 20th century.
The conclusion, I suppose, is that the leisure about which you are asking is not the same as the economic meaning of leisure (which is of course fine), and hopefully someone with expertise in the culture of leisure can pick up your answer on its own terms. However, there is clearly a sharp contrast between any image of easygoing bourgeois luxury, and the actual experience of the average French worker.