Larger land mass. Lower population density. Centres of population more dispersed. Capital city not in one corner of the country. Traditionally left of centre politically - more emphasis on state versus individualism.
Very different to the UK▸ .
I think that overstates the effect of geography. Great Britain and France are about the same length - 1000 miles - and Paris is almost as far off-centre as London, as well as being as dominant in economic and administrative terms. But there is a significant difference in their areas, as France is about the same length in any direction (it is known as
l'Hexagone) while
GB▸ is long and thin and tapers as you go north. The French population is also more evenly spread, since France has neighbours all round and the far end (from Paris) has warm weather; neither true of GB.
The area effect - twice as much per French head - does mean there is more space for railways, as well as roads, airports, or anything else. Cities of course create their own population density, so the extra space does not help there. Inversely, it would make the typical distance between people or places further, though only by 50%.
More important is the attitude to central government and its role in industry and business, which goes way back to Colbert or before. And a related factor, especially important in transport, is government centralisation - how much local government does. Fifty years ago everyone knew France was highly centralised, with its small
départements and even cities subject to central governemtn via a
préfet. However, in Britain by then the power of the municipalities had already been greatly reduced by wartime controls and subsequently. That has continued, so that local government in Britain now has little autonomy, while in France Mitterand's 1982 decentralisation plan has had a major impact. Not only has is given all levels of local government more to do and bigger budgets, but it created the regions which are big enough to control large budgets and were given the job of controlling transport.
National attitudes are misleading things, though. It's individuals that have the attitudes, and also have their own ides about what other's attitudes are, as do specific groups of people whose collective ideas can be seen as those of institutions. I reckon a lot of these perceptions about other's attitudes are decades out of date, or just plain wrong, as they can only be based on indirect reports (the media in some sense, who are another group with their own perceptions of others' attitudes). On the other hand the regional power structure is a real factor, and easier to observe.