Monier's son Pierre had moved to Noyon after the break with his father, established a family, and entered the same line of business, under the name "Monier fils". He probably returned to Paris in 1889, where he exhibited at the Exhibition of that year. The firm's projects included a reinforced concrete laundry building, and pipes for a sewage treatment plant. Unfortunately, Pierre died prematurely, apparently before 1900, without being reconciled with his father. By that year, a firm was trading as "Société des travaux en ciment de La Plaine-Saint-Denis, ancienne maison Monier fils" (i.e. formerly "Monier fils"). Projects completed by this firm include a partly in-ground reservoir at Vimoutier; an iconic elevated reservoir in the rustic style at Pontorson; the Cambodian Pavilion at the 1900 Exhibition; and two elevated reservoirs at Boullaye-Mivoie and Fonville, with their associated pump house.