What a great topic for discussion. Marie-Antoinette's infamous sisters-in-law are always left out of every movie, but they really were interesting and eccentric characters, and no discussion of the ancien-regime is complete without them. The Comtesse d'Artois had many descendants, including the Empress Zita. Both women, two sisters married to two brothers, had difficult marriages, which fell apart while in exile. Of course, Madame d'Artois cannot really be blamed for the separation; her husband ran off to Scotland with poor Mme. de Polastron. As for the Comtesse de Provence, she had other problems, including alcoholism, but was eventually reunited with her husband in what is now Latvia. Provence was at her side when she died in England in 1810, I believe.
There is a story about the old days at Versailles, when they were all teenagers together. Marie-Antoinette, who loved theatre even then, used to organize them into putting on plays in the attic of the chateau, with her husband Louis as the audience (everyone knew he was hopeless as an actor). Even Mme Elisabeth (who was quite small at the time) and Mme Colthilde (who had not yet married) would participate. The Comtesse d'Artois complained that it was not worthy of princesses of the House of Savoy to engage in play-acting. Her husband Artois rebuked her, feeling that she had just insulted his little sisters, saying, "What is good enough for a princess of France is good enough for a princess of Savoy," or something to that effect.