Comme la vérole sur le bas clergé

Literally: Like the pox on the lower clergy

Example: “Les contrôleurs sont tombés sur les resquilleurs comme la vérole sur le bas clergé.” — The inspectors came down on the fare dodgers like a ton of bricks.

English equivalent: To come down on someone like a ton of bricks

Origin: Vérole has meant several diseases: smallpox from the 12th to the 15th century, and chickenpox, as vérole volante, in the 17th. Since the 16th, though, and certainly here, it means syphilis. The phrase probably dates to the Ancien Régime, and its authors were plainly not warm admirers of the clergy — the whole force of it lies in the image of a venereal epidemic tearing through the parish priests, who have taken a vow of celibacy and could therefore not possibly be exposed to any such thing. The lower clergy were the priests and curates drawn from ordinary families and posted to parishes in the towns and the countryside, which is to say the ones people actually met. Some versions add a nationality — the Spanish lower clergy, the Breton lower clergy — and there is no evident reason why those should be singled out over the Auvergnat or the Alsatian, beyond the possibility that the priests were simply thicker on the ground.