In 1964, Air France already had a considerable network, one of the most extensive in the world. It served most major cities. Yet it didn't fly to Washington D.C.!
Not surprising, actually. Due to its eastern position and buoyancy, New York was the natural gateway for European companies to the United States. The seat of administrative and political power, Washington paradoxically stood back, preserving its so typically... provincial way of life. But things were changing. Driven by its demography (800,000 inhabitants in 1964), the city was modernizing. It had just acquired an international airport, which welcomed its first flights in late 1962.
The Paris-Washington route was officially launched on April 1, 1964. Three times a week, the two capitals were linked via New York by Boeing 707 with 148 seats (16 in 1st class; 132 in economy class). The trip lasted 10hr30 on the outward journey and 9hr on the return journey, including a 1hr30 stopover at J.F. Kennedy.
From 1976 to 1982, the route was favoured by the Concorde, before being suspended until 1985, when it resumed by subsonic B747. Since then, it has never left the Air France flight schedule.
Today, Air France serves Washington once or twice daily from Paris, by Boeing 777-300 or Airbus A380-800. Direct flights that last about 8hr30 on the outward journey and 7hr30 on the return journey.