[2] The award was given to the best science fiction novel published in France during the preceding year.
Awards were given for the years 1972-1990, inclusive, and usually went to a work first published in English in the US or UK.
[3] After the award ended in 1991, the Grand Prix de l'Imaginaire added a category for best Foreign-Language Novel (translated into French) to continue this category of award.
(Books 37-62 were published by Fleuve Noir in their own series starting in 1988.)
Aside from the later books in the La Compagnie des glaces series, all but three of these winning books are available in English as well as French, and most are available in other languages as well (see the ISFDB external link for details).