The total French metropolitan leveling network spans approximately 300,000 km and includes approximately 330,000 markers in good condition.
Notes on verification
Marker count (~330,000) is corroborated by an independent source; the 300,000 km network length figure has only order-of-magnitude support from an older Larousse entry using a different total marker count, and the exact IGN table pairing both figures with 'good condition' qualifier could not be directly confirmed.
Sources
- Les réseaux de nivellement français - Géodésie (geodesie.ign.fr)
- https://www.actu-alt-plus.com/tech-ia-futur/maregraphe-marseille-zero-altitudes-france/34196/ (actu-alt-plus.com)
- https://www.larousse.fr/archives/grande-encyclopedie/page/9633 (larousse.fr)