Collé relates the following story in his Memoirs regarding The Swing:
Successful painter Doyen was summoned by the Baron de Saint-Julien. The Baron received him in his home and overwhelmed him with compliments. He then indicated his mistress, saying: "I should like you to paint Madame seated on a swing and being pushed by a bishop. Me you shall place in a position where I can observe the legs of that charming girl, and better still if you want to enliven your picture..." Doyen, enraged to the point of speechlessness, managed to sputter Fragonard's name before taking his leave.
Saint-Julien was receiver general of the French clergy, and his witty and libertine painting was the rage of Paris, ensuring the success of Fragonard, whose scruples did not forswear the admiration of a pretty pair of legs ;-)