Money
Exact equivalences are, of course, impossible to establish but certain parallels can be made, especially since, before the First World War, European currencies were stable. The franc was common to France, Belgium, Switzerland and Italy, one for one, and the pound sterling was worth 25 of them. In 1900 a good average restaurant meal in France might cost 4 francs, a medium-class hotel room about 6, and a second-class rail ticket from Paris to Lyon 38. To post an ordinary letter within France cost 15 cents. The 250 francs a month Debussy earned playing Wagner every Saturday for Mme Escudier thus seems fairly modest, especially as it was more or less all he was earning at the time, and his later, much bigger advances (25,000 francs for the sale of Pelléas et Mélisande to Durand, 20,000 for Khamma, 20,000 for Le Martyre de Saint Sébastien) had to be set against the 3,600 per annum maintenance he had to pay Lilly Texier, his expensive Bois de Boulogne apartment, the lifestyle that went with it, and the fact that these sums were island peaks in a choppy sea. Needless to say, his medical treatment in his final years would have had to be paid for. He never received an adequate regular income, liked luxury and was a poor money manager.
Translations
Unless otherwise stated, all translations from French and Russian are my own, including in cases where published translations by others exist.