diff --git a/site/source/hooks/useIframeResizer.ts b/site/source/hooks/useIframeResizer.ts
index 6ac74f637..c4ae5436c 100644
--- a/site/source/hooks/useIframeResizer.ts
+++ b/site/source/hooks/useIframeResizer.ts
@@ -5,9 +5,7 @@ export function useIframeResizer() {
 		// The code below communicate with the iframe.js script on a host site
 		// to automatically resize the iframe when its inner content height
 		// change.
-		if (!window.location.search.includes('iframe')) {
-			return
-		}
+
 		const minHeight = 700 // Also used in iframe.js
 		const observer = new ResizeObserver(([entry]) => {
 			const value = Math.max(minHeight, entry.contentRect.height)
diff --git a/site/source/pages/Iframes/index.tsx b/site/source/pages/Iframes/index.tsx
index 438edcccb..14f1c1a37 100644
--- a/site/source/pages/Iframes/index.tsx
+++ b/site/source/pages/Iframes/index.tsx
@@ -25,7 +25,7 @@ export default function Iframes() {
 							s.iframePath && (
 								<Route
 									key={s.iframePath}
-									path={s.iframePath + '/*'}
+									path={'/' + encodeURI(s.iframePath) + '/*'}
 									element={
 										<>
 											<Helmet>
diff --git a/site/source/pages/Simulateurs/EconomieCollaborative/index.tsx b/site/source/pages/Simulateurs/EconomieCollaborative/index.tsx
index 974357b5e..3ecacda5b 100644
--- a/site/source/pages/Simulateurs/EconomieCollaborative/index.tsx
+++ b/site/source/pages/Simulateurs/EconomieCollaborative/index.tsx
@@ -16,7 +16,7 @@ export default function ÉconomieCollaborative() {
 	const iframePath =
 		useSimulatorsData()['économie-collaborative'].iframePath ?? ''
 	const indexPath = useIsEmbedded()
-		? `/iframes/${iframePath}`
+		? encodeURI(`/iframes/${iframePath}`)
 		: économieCollaborative.index
 
 	return (
diff --git a/site/source/pages/Simulateurs/Home.tsx b/site/source/pages/Simulateurs/Home.tsx
index 4e1aff656..df4e47cde 100644
--- a/site/source/pages/Simulateurs/Home.tsx
+++ b/site/source/pages/Simulateurs/Home.tsx
@@ -171,7 +171,8 @@ export function SimulateurCard({
 					<SmallCard
 						icon={<Emoji emoji={icône} />}
 						to={{
-							pathname: (isIframe && `/iframes/${iframePath ?? ''}`) || path,
+							pathname:
+								(isIframe && `/iframes/${encodeURI(iframePath ?? '')}`) || path,
 						}}
 						state={fromGérer ? { fromGérer: true } : { fromSimulateurs: true }}
 						title={
diff --git a/site/source/pages/integration/Iframe.tsx b/site/source/pages/integration/Iframe.tsx
index a63d28e97..24f8de9d1 100644
--- a/site/source/pages/integration/Iframe.tsx
+++ b/site/source/pages/integration/Iframe.tsx
@@ -59,13 +59,17 @@ function IntegrationCustomizer() {
 		''
 
 	const iframeRef = useRef<HTMLIFrameElement>(null)
-	const iframeSrc = useHref(`/iframes/${currentIframePath}?iframe`)
+	const iframeSrc = useHref(`/iframes/${currentIframePath}`)
 
 	useEffect(() => {
 		window.addEventListener(
 			'message',
 			function (evt: MessageEvent<{ kind: string; value: string }>) {
-				if (iframeRef.current && evt.data.kind === 'resize-height') {
+				if (
+					iframeRef.current &&
+					evt.data.kind === 'resize-height' &&
+					iframeRef.current.contentDocument?.readyState === 'complete'
+				) {
 					iframeRef.current.style.height = evt.data.value + 'px'
 				}
 			}