Many of the other key ministers kept their jobs.
Foreign Minister Jean-Noel Barrot retained his post, the presidency said.
Interior Minister Bruno Retailleau, who has vowed to crack down on illegal immigration, and Justice Minister Gerald Darmanin both stayed put.
Rachida Dati, a scandal-ridden culture minister who is to stand trial for corruption next year, also remained in place.
France has been mired in deadlock since Macron gambled on snap elections in the middle of last year in the hopes of bolstering his authority.
The move backfired, with voters electing a Parliament fractured between three rival blocs.
Lecornu’s two immediate predecessors, Francois Bayrou and Michel Barnier, were ousted in a legislative standoff over France’s austerity budget.
Lecornu is scheduled to deliver a general policy speech in Parliament on Tuesday.
Several left-wing parties have threatened to put forward a no-confidence motion against Lecornu.
-Agence France-Presse