diff --git a/build/cog.js b/build/cog.js
index 9588566..37c0f68 100644
--- a/build/cog.js
+++ b/build/cog.js
@@ -9,13 +9,22 @@ async function extractDepartements(path) {
   const rows = await readCsvFile(path)
 
   return rows.map(row => {
+    let zone
+    if (row.ZONE) {
+      zone = row.ZONE
+    } else if (row.DEP.length > 2) {
+      zone = 'dom'
+    } else {
+      zone = 'metro'
+    }
+
     return {
       code: row.DEP,
       region: row.REG,
       chefLieu: row.CHEFLIEU,
       nom: row.LIBELLE,
       typeLiaison: parseTypeLiaison(row.TNCC),
-      zone: row.ZONE ? row.ZONE : row.DEP.length > 2 ? 'dom' : 'metro'
+      zone
     }
   })
 }
@@ -24,12 +33,21 @@ async function extractRegions(path) {
   const rows = await readCsvFile(path)
 
   return rows.map(row => {
+    let zone
+    if (row.ZONE) {
+      zone = row.ZONE
+    } else if (['01', '02', '03', '04', '06'].includes(row.REG)) {
+      zone = 'dom'
+    } else {
+      zone = 'metro'
+    }
+
     return {
       code: row.REG,
       chefLieu: row.CHEFLIEU,
       nom: row.LIBELLE,
       typeLiaison: parseTypeLiaison(row.TNCC),
-      zone: row.ZONE ? row.ZONE : ['01', '02', '03', '04', '06'].includes(row.REG) ? 'dom' : 'metro'
+      zone
     }
   })
 }
@@ -118,11 +136,20 @@ async function extractCommunes(communesPath, mouvementsCommunesPath, arrondissem
   const anciensCodesIndex = computeAnciensCodesCommunes(communesRows, mouvementsRows)
 
   const communes = communesRows.map(row => {
+    let zone
+    if (row.zone) {
+      zone = row.zone
+    } else if (row.DEP.length > 2) {
+      zone = 'dom'
+    } else {
+      zone = 'metro'
+    }
+
     const commune = {
       code: row.COM,
       nom: row.LIBELLE,
       typeLiaison: parseTypeLiaison(row.TNCC),
-      zone: row.zone ? row.zone : row.DEP.length > 2 ? 'dom' : 'metro'
+      zone
     }
 
     if (row.TYPECOM === 'COM') {
diff --git a/build/index.js b/build/index.js
index 73da3cd..8d9a1e2 100644
--- a/build/index.js
+++ b/build/index.js
@@ -70,12 +70,12 @@ async function main() {
     communes: {...populationHorsMayotte.communes, ...populationMayotte.communes}
   }
   const arrondissements = await extractArrondissements(getSourceFilePath('arrondissements.csv'))
-  const departements_metro_and_dom = await extractDepartements(getSourceFilePath('departements.csv'))
-  const departements_com = await extractDepartements(getSourceFilePath('departements-outremer.csv'))
-  const departements = [...departements_metro_and_dom, ...departements_com]
-  const regions_metro_and_dom = await extractRegions(getSourceFilePath('regions.csv'))
-  const regions_com = await extractRegions(getSourceFilePath('regions-outremer.csv'))
-  const regions = [...regions_metro_and_dom, ...regions_com]
+  const departementsMetroAndDom = await extractDepartements(getSourceFilePath('departements.csv'))
+  const departementsCom = await extractDepartements(getSourceFilePath('departements-outremer.csv'))
+  const departements = [...departementsMetroAndDom, ...departementsCom]
+  const regionsMetroAndDom = await extractRegions(getSourceFilePath('regions.csv'))
+  const regionsCom = await extractRegions(getSourceFilePath('regions-outremer.csv'))
+  const regions = [...regionsMetroAndDom, ...regionsCom]
 
   await buildRegions(regions)
   await buildDepartements(departements)