Men whose only concern is other people’s opinion of them are like actors who put on a poor performance to win the applause of people of poor taste; some of them would be capable of good acting in front of a good audience. A decent man plays his part to the best of his ability, regardless of the taste of the gallery.

[Ceux qui rapportent tout à l’opinion ressemblent à ces comédiens qui jouent mal pour être applaudis, quand le goût du Public est mauvais. Quelques-uns auraient le moyen de bien jouer si le goût du Public était bon. L’honnête homme joue son rôle le mieux qu’il peut, sans songer à la galerie.]

Nicolas Chamfort (1741-1794) French writer, epigrammist (b. Nicolas-Sébastien Roch)

Products of Perfected Civilization [Produits de la Civilisation Perfectionée], Part 1 “Maxims and Thoughts [Maximes et Pensées],” ch. 2, ¶ 141 (1795) [tr. Parmée (2003), ¶ 117]
    (Source)

(Source (French)). Alternate translations:

Those who refer everything to the opinion of others are like comedians who act badly, when the public taste is bad, in order to be applauded. Some of them could have acted well if the taste of the audience had been good. An upright man plays his part as excellently as he can, with no thought for the gallery.
[tr. Mathers (1926)]

Those who defer in everything to the general opinion are like actors who act badly in the hope of applause, when the public’s taste is bad. Some of them would be able to act well, if the public’s taste were good. An honest man plays his part as well as he can, without a thought for the gallery.
[tr. Merwin (1969)]

Those who refer everything to public opinion are like those actors who play badly in order to be applauded, when public taste is bad. some would have an opportunity to act well, if public taste were good. The respectable man plays his part as best he can, without thinking of the gallery.
[tr. Pearson (1973)]