diff --git a/components/codev/CodevGraph.vue b/components/codev/CodevGraph.vue
index 97764d3..5d2347c 100644
--- a/components/codev/CodevGraph.vue
+++ b/components/codev/CodevGraph.vue
@@ -8,7 +8,21 @@
     </div>
 
     <!-- SVG D3 -->
-    <svg v-else ref="svgEl" class="codev-svg" />
+    <svg v-else ref="svgEl" class="codev-svg">
+      <defs>
+        <marker
+          id="arrow-solution"
+          viewBox="0 0 10 10"
+          refX="18"
+          refY="5"
+          markerWidth="6"
+          markerHeight="6"
+          orient="auto-start-reverse"
+        >
+          <path d="M 0 0 L 10 5 L 0 10 z" fill="#22c55e" />
+        </marker>
+      </defs>
+    </svg>
 
   </div>
 </template>
@@ -82,9 +96,9 @@ function buildLinks(nodes: SimNode[]): SimLink[] {
 }
 
 function linkColor(mode: string): string {
-  if (mode === 'solution') return '#1B4436'
-  if (mode === 'alliance') return '#3b82f6'
-  if (mode === 'surprise') return '#a855f7'
+  if (mode === 'solution') return '#22c55e'
+  if (mode === 'alliance') return '#f97316'
+  if (mode === 'surprise') return '#3b82f6'
   return '#ccc'
 }
 
@@ -132,8 +146,6 @@ function rebuildLinks() {
   currentLinks = buildLinks(currentNodes)
   if (!gLinks || !simulation) return
 
-  const r = nodeRadius.value
-
   const linkSel = gLinks
     .selectAll<SVGLineElement, SimLink>('line')
     .data(currentLinks, (d: SimLink) => {
@@ -149,7 +161,7 @@ function rebuildLinks() {
     .attr('stroke', d => linkColor(d.mode))
     .attr('stroke-width', d => 1 + d.score * 3)
     .attr('stroke-opacity', 0.7)
-    .attr('marker-end', null)
+    .attr('marker-end', d => d.mode === 'solution' ? 'url(#arrow-solution)' : null)
 }
 
 // ── Rendu complet ──────────────────────────────────────────────────────────
@@ -173,6 +185,7 @@ function render() {
     .attr('stroke', d => linkColor(d.mode))
     .attr('stroke-width', d => 1 + d.score * 3)
     .attr('stroke-opacity', 0.7)
+    .attr('marker-end', d => d.mode === 'solution' ? 'url(#arrow-solution)' : null)
 
   // Noeuds = groupe <g> par personne
   const nodeGroups = gNodes!
diff --git a/pages/codev/carto.vue b/pages/codev/carto.vue
index 4939cd5..88e11db 100644
--- a/pages/codev/carto.vue
+++ b/pages/codev/carto.vue
@@ -6,7 +6,7 @@
       <p class="carto-subtitle">
         <template v-if="pending">Chargement...</template>
         <template v-else>
-          {{ fiches.length }} fiche{{ fiches.length !== 1 ? 's' : '' }} — clique sur un nom pour voir le detail
+          {{ fiches.length }} fiche{{ fiches.length !== 1 ? 's' : '' }} - clique sur un nom pour voir le detail
         </template>
       </p>
     </header>
@@ -23,9 +23,52 @@
       </template>
     </ClientOnly>
 
-    <!-- Boutons matching : arrivent en M4 -->
-    <div class="matching-controls placeholder">
-      <p>Boutons matching - arrivent bientot (M4)</p>
+    <!-- Bandeau info mode actif -->
+    <div v-if="mode !== 'none'" class="mode-banner">
+      <span>
+        Mode {{ MODE_LABELS[mode] }} actif -
+        {{ matches.length }} connexion{{ matches.length !== 1 ? 's' : '' }} trouvee{{ matches.length !== 1 ? 's' : '' }}.
+      </span>
+      <button class="banner-clear" @click="setMode('none')" type="button">Effacer</button>
+    </div>
+
+    <!-- Boutons matching -->
+    <div class="matching-controls">
+      <button
+        :class="{ active: mode === 'solution' }"
+        style="--mode-color: #22c55e"
+        @click="setMode('solution')"
+        type="button"
+      >
+        Solution
+        <span class="hint">besoin - offre</span>
+      </button>
+      <button
+        :class="{ active: mode === 'alliance' }"
+        style="--mode-color: #f97316"
+        @click="setMode('alliance')"
+        type="button"
+      >
+        Alliance
+        <span class="hint">besoins partages</span>
+      </button>
+      <button
+        :class="{ active: mode === 'surprise' }"
+        style="--mode-color: #3b82f6"
+        @click="setMode('surprise')"
+        type="button"
+      >
+        Surprise
+        <span class="hint">offres partagees</span>
+      </button>
+      <button
+        v-if="mode !== 'none'"
+        class="reset"
+        @click="setMode('none')"
+        type="button"
+      >
+        Effacer
+      </button>
     </div>
 
   </div>
@@ -33,18 +76,32 @@
 
 <script setup lang="ts">
 import type { CodevFiche, CodevMatch } from '~/types/codev'
+import { computeMatches } from '~/utils/codev/matching'
 
-useHead({ title: 'Carto — Co-developpement' })
+useHead({ title: 'Carto - Co-developpement' })
 
 const { data, pending } = await useFetch<{ list: CodevFiche[] }>('/api/codev/fiches')
 const fiches = computed(() => data.value?.list ?? [])
 
-// En M3 : pas de matching, tableau vide. M4 remplira ces refs.
 const matches = ref<CodevMatch[]>([])
 const mode = ref<'none' | 'solution' | 'alliance' | 'surprise'>('none')
 
+const MODE_LABELS: Record<string, string> = {
+  solution: 'Solution',
+  alliance: 'Alliance',
+  surprise: 'Surprise',
+}
+
+function setMode(newMode: 'none' | 'solution' | 'alliance' | 'surprise') {
+  mode.value = newMode
+  if (newMode === 'none') {
+    matches.value = []
+  } else {
+    matches.value = computeMatches(fiches.value, newMode)
+  }
+}
+
 function onSelectFiche(id: number) {
-  // M3 : simple navigation vers la fiche (ou futur drawer en M4)
   navigateTo(`/codev/fiche?id=${id}`)
 }
 </script>
@@ -96,17 +153,107 @@ function onSelectFiche(id: number) {
   border-radius: 12px;
 }
 
-/* ── Placeholder matching (M4) ── */
+/* ── Bandeau mode actif ── */
 
-.matching-controls.placeholder {
-  text-align: center;
-  padding: 0.75rem;
+.mode-banner {
+  display: flex;
+  align-items: center;
+  justify-content: space-between;
+  gap: 0.75rem;
+  padding: 0.5rem 0.875rem;
+  background: #f0fdf4;
+  border: 1px solid #bbf7d0;
+  border-radius: 8px;
+  font-size: 0.875rem;
+  color: #166534;
+  flex-wrap: wrap;
 }
 
-.matching-controls.placeholder p {
-  color: #999;
-  font-size: 0.85rem;
-  margin: 0;
+.banner-clear {
+  font-size: 0.8rem;
+  font-weight: 600;
+  color: #166534;
+  background: transparent;
+  border: 1px solid #166534;
+  border-radius: 6px;
+  padding: 0.2rem 0.6rem;
+  cursor: pointer;
+  white-space: nowrap;
+}
+
+.banner-clear:hover {
+  background: #166534;
+  color: #fff;
+}
+
+/* ── Boutons matching ── */
+
+.matching-controls {
+  position: sticky;
+  bottom: 0;
+  display: flex;
+  gap: 8px;
+  padding: 12px;
+  background: rgba(255, 255, 255, 0.95);
+  backdrop-filter: blur(8px);
+  border-top: 1px solid #e5e7eb;
+  margin: 0 -1rem -2rem;
+}
+
+.matching-controls button {
+  flex: 1;
+  padding: 12px 8px;
+  border: 1px solid #d0d4dc;
+  border-radius: 8px;
+  background: white;
+  font-size: 14px;
+  cursor: pointer;
+  display: flex;
+  flex-direction: column;
+  align-items: center;
+  gap: 2px;
+  transition: background 0.15s, color 0.15s, border-color 0.15s;
+}
+
+.matching-controls button .hint {
+  font-size: 11px;
+  color: #6b7280;
+  font-weight: normal;
+}
+
+.matching-controls button.active {
+  background: var(--mode-color, #1B4436);
+  color: white;
+  border-color: transparent;
+}
+
+.matching-controls button.active .hint {
+  color: rgba(255, 255, 255, 0.8);
+}
+
+.matching-controls button.reset {
+  flex: 0 0 auto;
+  padding: 12px 16px;
+  background: #f3f4f6;
+  border-color: #d0d4dc;
+  color: #374151;
+  font-size: 13px;
+}
+
+.matching-controls button.reset:hover {
+  background: #e5e7eb;
+}
+
+@media (max-width: 500px) {
+  .matching-controls {
+    display: grid;
+    grid-template-columns: repeat(2, 1fr);
+    margin: 0 -0.75rem -1.5rem;
+  }
+
+  .matching-controls button.reset {
+    grid-column: span 2;
+  }
 }
 
 /* ── Mobile ── */
diff --git a/utils/codev/matching.ts b/utils/codev/matching.ts
new file mode 100644
index 0000000..fe3135b
--- /dev/null
+++ b/utils/codev/matching.ts
@@ -0,0 +1,97 @@
+import type { CodevFiche, CodevMatch } from '~/types/codev'
+
+const STOP_WORDS_FR = new Set([
+  'le', 'la', 'les', 'un', 'une', 'des', 'de', 'du', 'au', 'aux',
+  'et', 'ou', 'mais', 'donc', 'car', 'ni', 'or',
+  'a', 'en', 'pour', 'par', 'sur', 'avec', 'sans', 'dans', 'sous',
+  'je', 'tu', 'il', 'elle', 'on', 'nous', 'vous', 'ils', 'elles',
+  'mon', 'ma', 'mes', 'ton', 'ta', 'tes', 'son', 'sa', 'ses',
+  'notre', 'nos', 'votre', 'vos', 'leur', 'leurs',
+  'ce', 'cet', 'cette', 'ces', 'qui', 'que', 'quoi', 'dont',
+  'est', 'sont', 'etre', 'ai', 'as', 'avoir',
+  'pas', 'plus', 'moins', 'tres', 'aussi', 'bien', 'tout', 'tous',
+  'me', 'te', 'se', 'lui', 'leur', 'y',
+])
+
+function tokenize(text: string): Set<string> {
+  if (!text) return new Set()
+  const tokens = text
+    .toLowerCase()
+    .replace(/[.,;:!?()'"\-/]/g, ' ')
+    .split(/\s+/)
+    .filter((t) => t.length >= 3 && !STOP_WORDS_FR.has(t))
+  return new Set(tokens)
+}
+
+function jaccard(a: Set<string>, b: Set<string>): number {
+  if (a.size === 0 || b.size === 0) return 0
+  let inter = 0
+  for (const x of a) if (b.has(x)) inter++
+  const union = a.size + b.size - inter
+  return union === 0 ? 0 : inter / union
+}
+
+function score(textA: string, hashtagsA: string[], textB: string, hashtagsB: string[]): number {
+  const tagsA = new Set(hashtagsA.map((h) => h.toLowerCase()))
+  const tagsB = new Set(hashtagsB.map((h) => h.toLowerCase()))
+
+  if (tagsA.size > 0 && tagsB.size > 0) {
+    return jaccard(tagsA, tagsB)
+  }
+  return jaccard(tokenize(textA), tokenize(textB))
+}
+
+const THRESHOLD = 0.15
+
+export function matchSolution(fiches: CodevFiche[]): CodevMatch[] {
+  const matches: CodevMatch[] = []
+  for (const a of fiches) {
+    for (const b of fiches) {
+      if (a.id === b.id) continue
+      const s = score(a.besoin, a.hashtags, b.offre, b.hashtags)
+      if (s >= THRESHOLD) {
+        matches.push({ fromId: a.id, toId: b.id, score: s, mode: 'solution' })
+      }
+    }
+  }
+  return matches
+}
+
+export function matchAlliance(fiches: CodevFiche[]): CodevMatch[] {
+  const matches: CodevMatch[] = []
+  for (let i = 0; i < fiches.length; i++) {
+    for (let j = i + 1; j < fiches.length; j++) {
+      const a = fiches[i], b = fiches[j]
+      const s = score(a.besoin, a.hashtags, b.besoin, b.hashtags)
+      if (s >= THRESHOLD) {
+        matches.push({ fromId: a.id, toId: b.id, score: s, mode: 'alliance' })
+      }
+    }
+  }
+  return matches
+}
+
+export function matchSurprise(fiches: CodevFiche[]): CodevMatch[] {
+  const matches: CodevMatch[] = []
+  for (let i = 0; i < fiches.length; i++) {
+    for (let j = i + 1; j < fiches.length; j++) {
+      const a = fiches[i], b = fiches[j]
+      const s = score(a.offre, a.hashtags, b.offre, b.hashtags)
+      if (s >= THRESHOLD) {
+        matches.push({ fromId: a.id, toId: b.id, score: s, mode: 'surprise' })
+      }
+    }
+  }
+  return matches
+}
+
+export function computeMatches(
+  fiches: CodevFiche[],
+  mode: 'solution' | 'alliance' | 'surprise',
+): CodevMatch[] {
+  switch (mode) {
+    case 'solution': return matchSolution(fiches)
+    case 'alliance': return matchAlliance(fiches)
+    case 'surprise': return matchSurprise(fiches)
+  }
+}