Ouvrage Le Lavoir, Military fortification in Modane, France

Ouvrage Le Lavoir is a Maginot Line artillery work on the adret above Valfréjus, at Le Collet in the Charmaix valley at 1,923 m. Its seven surface blocks are dispersed on the slope, with two separate entries: a personnel entry at ground level and a supply entry beside the valley road. The work was never finished; a 195 m inclined plane at 58% with a 537-step stair links the lower entry to the galleries.

The ouvrage was never finished, so the 1932–1939 construction dates are wrong. In June 1940 its guns fired 3,818 shots, the most of any ouvrage in the Maurienne, including on Italian troops on the surface of Pas-du-Roc; a mortar explosion wounded two gunners. The 25 June armistice ended the fighting, and the site was recaptured on 13 September 1944.

The name Lavoir comes from the hamlet of Le Collet in the Charmaix valley, above the Valfréjus ski resort. The surface barracks in the valley were linked to Charmaix by an aerial tramway. The white sign at the entrance reads "ARMES FORTES" over "DANGER", a warning about the weapons kept in the ouvrage.

The site has two separate entrances serving different functions: one for ammunition transport and another for personnel movement. Visitors should expect cool underground spaces with sturdy footwear recommended for navigating the interior.

The ouvrage was never finished: its galleries, 60 cm railway and 195 m inclined plane climbing at 58% were built, but the work stopped short of completion. The inclined plane was fitted with an electric winch, alongside a staircase of 537 steps.