France has had family taxation; however, they also have a very different approach to taxation. They tax capital, they tax wealth, they pay families to have a parent stay at home for five years. They have female labour force participation that is 10% lower than here in Canada.
In the U.S., they give people the option. Do they want to opt to be taxed as families or taxed as individuals?
What you see, at least in the most recent tax data, is a pretty clear relationship that higher-income individuals choose to file jointly. Why? Because they get more bang for their buck out of it.