The fundamental reference marker for the NGF/IGN69 system, designated M.AC-0-VIII, is located inside the buildings of the Marseille Tide Gauge.
Notes on verification
Confirmed by IGN's own geodesy documentation and corroborated by multiple independent governmental (SHOM), academic, and specialist sources, all consistent with no contradictions.
Sources
- Les réseaux de nivellement français - Géodésie (geodesie.ign.fr)
- https://www.aftopo.org/lexique/repere-fondamental-du-ngf/ (aftopo.org)
- https://refmar.shom.fr/references-de-hauteur-en-maregraphie (refmar.shom.fr)
- https://journals.openedition.org/ephaistos/8716?lang=en (journals.openedition.org)