In retirement, Monier was harassed by bailiffs and by the tax office, which reasoned that he should have been receiving large commissions from his many foreign patents. He sought refuge in the house of his son Lucien, by his second wife. In 1902 a number of foreign firms that had profited from his patents appealed to the President of France to grant him a pension, describing him as the inventor of reinforced concrete, and as their "former master" (ancien maître). They opened a subscription for his benefit, and contributions came from far afield. A petition was later organised asking that he be granted a post running a government tobacco kiosk. Monier expressed his gratitude for these efforts in a letter published in the journal "Le Ciment" in 1902. He died on 13 March 1906 and was buried in the municipal cemetery of Billancourt. The "Société des travaux en ciment" was still in operation in that year, when it exhibited at the Paris Exhibition.