diff --git a/src/screens/Writing/CustomizeSongStructure.js b/src/screens/Writing/CustomizeSongStructure.js
index 8168f25..7b20779 100644
--- a/src/screens/Writing/CustomizeSongStructure.js
+++ b/src/screens/Writing/CustomizeSongStructure.js
@@ -2,6 +2,7 @@ import React, { useCallback, useEffect, useMemo, useState } from 'react'
 import { FlatList, Image, StyleSheet, Text, TouchableOpacity, View } from 'react-native'
 import Animated, { useAnimatedRef } from 'react-native-reanimated'
 import Sortable from 'react-native-sortables'
+import { useGlobal } from 'reactn'
 import { icons } from '../../assets'
 import { Palette } from '../../styles'
 import { FONT_FAMILY } from '../../styles/Fonts'
@@ -21,6 +22,11 @@ const createSortableItem = (type, index = 0) => ({
   type,
   value: type,
 })
+const PRE_REFRAIN_TYPE = 'pre_refrain_instrumental'
+const INTRO_TYPES = new Set(['short_intro', 'long_intro', 'intro', 'introduction'])
+const PRE_REFRAIN_ERROR_MESSAGE =
+  'Impossible de positionner un pré-refrain ici. Place-le juste avant un refrain.'
+const INTRO_ERROR_MESSAGE = "L'introduction musicale doit rester en première position."
 const SANITIZE_OPTIONS = { autoInjectPreChorus: false }
 
 const buildSortableItems = (values = []) =>
@@ -28,8 +34,36 @@ const buildSortableItems = (values = []) =>
     createSortableItem(type, index)
   )
 
+const validateStructureRules = (values = []) => {
+  for (let index = 0; index < values.length; index += 1) {
+    const type = values[index]
+    if (type === PRE_REFRAIN_TYPE) {
+      const nextType = values[index + 1]
+      if (nextType !== 'refrain') {
+        return {
+          valid: false,
+          reason: 'pre_refrain_invalid_position',
+          message: PRE_REFRAIN_ERROR_MESSAGE,
+        }
+      }
+    }
+  }
+
+  const introIndex = values.findIndex((type) => INTRO_TYPES.has(type))
+  if (introIndex > 0) {
+    return {
+      valid: false,
+      reason: 'intro_must_be_first',
+      message: INTRO_ERROR_MESSAGE,
+    }
+  }
+
+  return { valid: true }
+}
+
 const CustomizeSongStructure = ({ baseStructure = [], onChange }) => {
   const scrollRef = useAnimatedRef()
+  const [, setTooltip] = useGlobal('_tooltip')
   const sanitizedBase = useMemo(
     () => sanitizeStructureList(baseStructure, SANITIZE_OPTIONS),
     [baseStructure]
@@ -39,6 +73,13 @@ const CustomizeSongStructure = ({ baseStructure = [], onChange }) => {
     []
   )
   const [sortableItems, setSortableItems] = useState(() => buildSortableItems(sanitizedBase))
+  const showTooltip = useCallback(
+    (text, type = 'error') => {
+      if (!text) return
+      setTooltip({ text, type })
+    },
+    [setTooltip]
+  )
 
   useEffect(() => {
     setSortableItems((prev) => {
@@ -119,12 +160,32 @@ const CustomizeSongStructure = ({ baseStructure = [], onChange }) => {
           return buildSortableItems(sanitized)
         }
 
-        nextValues.push(type)
+        if (type === PRE_REFRAIN_TYPE) {
+          const firstRefrainIndex = nextValues.findIndex((value) => value === 'refrain')
+          if (firstRefrainIndex === -1) {
+            showTooltip(PRE_REFRAIN_ERROR_MESSAGE)
+            return prev
+          }
+          nextValues.splice(firstRefrainIndex, 0, type)
+        } else if (meta?.exclusiveGroup === 'intro') {
+          nextValues.unshift(type)
+        } else if (meta?.exclusiveGroup === 'outro') {
+          nextValues.push(type)
+        } else {
+          nextValues.push(type)
+        }
+
+        const validation = validateStructureRules(nextValues)
+        if (!validation.valid) {
+          showTooltip(validation.message)
+          return prev
+        }
+
         const sanitized = sanitizeStructureList(nextValues, SANITIZE_OPTIONS)
         return buildSortableItems(sanitized)
       })
     },
-    [extractValues]
+    [extractValues, showTooltip]
   )
 
   const Row = ({ item: rowData, onPress }) => {
@@ -201,6 +262,12 @@ const CustomizeSongStructure = ({ baseStructure = [], onChange }) => {
               scrollableRef={scrollRef}
               onDragEnd={({ data: newData }) => {
                 const values = extractValues(newData)
+                const validation = validateStructureRules(values)
+                if (!validation.valid) {
+                  showTooltip(validation.message)
+                  setSortableItems((prev) => buildSortableItems(extractValues(prev)))
+                  return
+                }
                 const sanitized = sanitizeStructureList(values, SANITIZE_OPTIONS)
                 setSortableItems(buildSortableItems(sanitized))
               }}