French knives mainly use stainless steels with about 55 HRC hardness, easier to maintain. A sharpening steel is then the best tool to use.
French knives are thus associated with a better quality/price ratio over time.
Knives are made according to culinary habits … In Japan, blades reply to specific specific product and way of cutting it : for example, Nakiri is for vegetables, Yanagi Ba is for sashimis… Handles are very simple and similar to each other: straight, in wood, most of the time.
Finally, the technique required to handle Japanese knives means that they are not suitable for everybody and/or for everyday use.
French knives replies to larger needs even if some are more adapted to vegetables, other to fishes and other to meat.
Ergonomics and aesthetics are very important to relieve hand and arm. Efficiency (one blade for one action) and resistance (especially for washing in the dishwasher!), and ease of use and maintain… are also delopped, for use intended for professionals and attainable for individuals.