Begin with Paris’s art collections and hillside streets, travel east to the waterways of Alsace, then continue through Lyon to Nice. This ten-day journey gives each city a different purpose: two full Paris days for a museum and Montmartre, Strasbourg for a close look at French and German architectural traditions, Lyon for Renaissance courtyards and regional cooking, and Nice for the old town beside the sea. The overnight sequence is three nights in Paris, two in Strasbourg, two in Lyon and two in Nice. You leave Nice on day ten. Trains connect all four central stations, so there is no reason to hire a car for this urban holiday. May, June and September suit the walking and outdoor meals; plan the Riviera stay around culture and the coast, with swimming as an optional extra. Strasbourg is an eastward detour from the simpler Paris–Lyon–Nice line, but its half-timbered houses, imperial avenues and Alsatian dishes reward the extra train journey.