lambert-rust is a crate helping to convert Lambert coordinates to WGS84.
let point = Point::new(369419.0, 1986498.0, 0.0)
.wgs84_from_meter(Zone::Lambert93)
.convert_unit(AngleUnit::Radian, AngleUnit::Degree);
println!("WGS84 Lat:{}, Lon:{}", point.y, point.x);