this is really a matter opinion. Most French design houses have been around longer than American design houses and are now designed by designers other than the original designer. (For example, Chanel is now designed by Karl Lagerfield, Lanvin is designed by Alber Elbaz, and Balenciaga is designed by Nichola Ghesquire.) But many people might prefer American designs which can be considered a bit more casual and ready-to-wear. It is all a matter of opinion.

French Haute Couture fashions were the best clothes made for many years.  American designers always strived to meet those standards of excellence, set by the great French Designers like Givenchy, and Dior. The French used the best fabrics, trims, and beading, and they put thousands of hours into hand cutting patterns, and hand sewing trims, laces, and other embellishments.   These garments were made to fit extremely tall, thin, women.  Americans are not built that way, and overtime what sold in the U.S.A. was comfort and simplicity.  The name the Americans gave their clothes was ready-to-wear.  These clothes were simply constructed, fit well on many body shapes,  made from everyday fabrics like denim and gabardine, cotton and wool.  These clothes worn well, and were designed to stay in style.   People of every age began to like the feel of comfortable, wearable, price-friendly clothes.  The great designers in France did not put much faith in ready-to-wear, but about 1960 they saw a decline in Haute Couture.  Smaller and smaller groups of women could afford them, and many found these clothes pricey and hard to wear.   The Japanese loved French fashion and bought is as fast as they could find it, but eventually, they too began to look for better prices and more comfort.  The great French Designers retired of passed away, and British  Designers began to run the famous French shops.  They are doing there best, but right now, young people and “fashionistas” in Europe are dressing American in London, France, Russia and even Japan.  Where people used to demand creativity and imagination in design; now wearable, comfortable and  simple American design rules.