A Concorde is currently tracked from Paris CDG to New York JFK Airport on flightradar24.
An Air France Concorde is currently tracked by over 20K people on flightradar24 tracking website.
The plane (huge icon) is flying form Paris CDG to New York JFK at 1,300 kt, over 50,000 feet altitude.
Unfortunately, the Concorde with registration F-BTSD is preserved at the Musée de l’air et de l’espace in Paris and doesn’t fly anymore.

Later, the website repeated the April fool with a British Airways Concorde (registration G-BOAG) leaving London Heathrow to JFK Airport.
But the well prepared joke was that good that it made the website to crash.

In 2003, Air France and British Airways announced the retirement of Concorde, due to rising maintenance costs, low passenger numbers following the 25 July 2000 crash, and the slump in air travel following the September 11 attacks.
Air France flew its last commercial flight on 30 May 2003 with British Airways retiring its Concorde fleet on 24 October 2003.
In 2000, Air France Flight 4590 (registration F-BTSC) carrying 100 passengers and 9 crew members has crashed after takeoff form Paris CDG.
The aircraft was overloaded by 810 kilograms (1,790 lb) above the maximum safe takeoff weight. Any effect on takeoff performance from this excess weight was negligible.