The interwar years were marked by the town's reconstruction. The State provided support in the form of "war compensation" The local authority put together a programme of alignment, planning and expansion. The basic ideas were: repair and widening of the roads, removal of level crossings, hygiene and embellishment of the town. The marshlands that had been drained and filled in were then included in the town's expansion plans. Saint-Leger church, the town hall, the Grands Bureaux of the Mining Company (currently occupied by the Université d’Artois) with its magnificent French gardens and the station were built and rebuilt during this period. The building of the latter was listed in the Historical Monuments register ("inventaire supplémentaire"). The reconstruction was making good progress from 1926.
As for privately owned buildings, the landlords rebuilt them by forming a cooperative reconstruction group called "the Union of disaster stricken landlords of Lens", that operated from 5th August 1921 to 6th July 1932. There was no particular requirements regarding style. The resulting main streets are harmonious in appearance despite the variety of designs. Some of the beautiful buildings in the town centre were inspired by the "Hispano-Flemish" style. The materials used were essentially bricks, reinforced concrete and tiles. The mining towns spread out as well.