Is lemon meringue pie French?

No. Lemon custard/pudding/curd is a product of the European Renaissance, and meringue was invented originally by a Swiss Chef. Lemon meringue pie as we know it is a fairly recent invention by comparison, since meringue has been around since the 17th century, and the pie's earliest recipes put it in the 19th century. It is said to have first been seen in America in Philadelphia when Elizabeth Coane Goodfellow introduced it in her shops. The first recorded recipe for it is from 1769, but it wasn't called Lemon Meringue Pie yet.