The writer who considers only the taste of his own time is concerned more with his personal fame than with that of his books: we should always aim at perfection, and then we shall receive from posterity that justice which our contemporaries sometimes deny us.

[Celui qui n’a égard en écrivant qu’au goût de son siècle songe plus à sa personne qu’à ses écrits: il faut toujours tendre à la perfection, et alors cette justice qui nous est quelquefois refusée par nos contemporains, la postérité sait nous la rendre.]

Jean de La Bruyère (1645-1696) French essayist, moralist

The Characters [Les Caractères], ch. 1 “Of Works of the Mind [Des Ouvrages de l’Esprit],” § 67 (1.67) (1688) [tr. Stewart (1970)]
    (Source)

(Source (French)). Alternate translations:

He who regards nothing more in his Works than the taste of the Age, has a greater value for his Person than his Writings: He should always aim at Perfection; and tho his Contemporaries refuse him Justice, Posterity will give it him.
[Bullord ed. (1696)]

He who regards nothing more in his Works than the Taste of his own Age, Considers his Person more than his Writings: He should always aim at Perfection, and tho his Contemporaries refuse him Justice, Posterity will give it him.
[Curll ed. (1713)]

He who regards nothing more in his Works than the Taste of the Age, has a greater value for his Person than his Writings: He should always aim at Perfection; and though his Cotempararies refuse him Justice, he will be better used by Posterity.
[Browne ed. (1752)]

He who only writes to suit the taste of the age, considers himself more than his writings. We should always aim at perfection, and then posterity will do us that justice which sometimes our contemporaries refuse.
[tr. Van Laun (1885)]