When and which country bought the patent right of photography in Daguerre?

Daguerre found astronomer and congressman arago (1786 ~ 1853), hoping that he could come forward to persuade the government to buy his own invention. After seeing the image on the metal plate, the visionary arago "almost fainted with excitement", and he immediately realized that it was an epoch-making invention.

1839, strongly recommended by arago and another member of parliament, Guy Lussac, the French government bought the patent right of Daguerre's photography, and announced it to the whole country, so that everyone could use the invention for free. As a reward, the French government pays Daguerre 6000 francs a year and Nipps's son 4000 francs for life.