According to the book "The Industrial Revolution In Iron: The Impact Of British Coal Technology In Nineteenth-Century Europe" by Chris Evans and Göran Rydén, a list of workers was made in April 1824 at the Charenton Ironworks. There were 135 names, 84 with wives, for a total of 216 adults. Most workers were between 20 and 30 years old and came from Staffordshire. Among the names were a few Griffiths. Maybe someone has a copy of that list and could check for James Griffith.

Most births, marriages and deaths were recorded to the British Embassy and not necessarily recorded in the French records. So you might try and find who holds those records. I have heard that the Guildhall Library in London has records like that.

Best of luck.