diff --git a/addons/web_editor/static/lib/odoo-editor/src/commands/commands.js b/addons/web_editor/static/lib/odoo-editor/src/commands/commands.js
index 0f4b8010c56..ed072c66108 100644
--- a/addons/web_editor/static/lib/odoo-editor/src/commands/commands.js
+++ b/addons/web_editor/static/lib/odoo-editor/src/commands/commands.js
@@ -33,6 +33,9 @@ import {
     splitTextNode,
     startPos,
     nodeSize,
+    allowsParagraphRelatedElements,
+    isUnbreakable,
+    makeContentsInline,
 } from '../utils/utils.js';
 
 const TEXT_CLASSES_REGEX = /\btext-[^\s]*\b/g;
@@ -71,13 +74,18 @@ function insert(editor, data, isText = true) {
     let nodeToInsert;
     const insertedNodes = [...fakeEl.childNodes];
     while ((nodeToInsert = fakeEl.childNodes[0])) {
-        if (isBlock(nodeToInsert) && !isBlock(startNode)) {
+        if (isBlock(nodeToInsert) && !allowsParagraphRelatedElements(startNode)) {
             // Split blocks at the edges if inserting new blocks (preventing
             // <p><p>text</p></p> scenarios).
             while (
                 startNode.parentElement !== editor.editable &&
-                !isBlock(startNode.parentElement)
+                !allowsParagraphRelatedElements(startNode.parentElement)
             ) {
+                if (isUnbreakable(startNode.parentElement)) {
+                    makeContentsInline(fakeEl);
+                    nodeToInsert = fakeEl.childNodes[0];
+                    break;
+                }
                 let offset = childNodeIndex(startNode);
                 if (!insertBefore) {
                     offset += 1;
diff --git a/addons/web_editor/static/lib/odoo-editor/src/utils/utils.js b/addons/web_editor/static/lib/odoo-editor/src/utils/utils.js
index 55ee0a0cf8c..c6ecc28572a 100644
--- a/addons/web_editor/static/lib/odoo-editor/src/utils/utils.js
+++ b/addons/web_editor/static/lib/odoo-editor/src/utils/utils.js
@@ -800,7 +800,7 @@ export function preserveCursor(document) {
  * Source:
  * https://developer.mozilla.org/en-US/docs/Web/HTML/Block-level_elements
  *
- * */
+ **/
 const blockTagNames = [
     'ADDRESS',
     'ARTICLE',
@@ -985,6 +985,53 @@ export function getInSelection(document, selector) {
     );
 }
 
+// This is a list of "paragraph-related elements", defined as elements that
+// behave like paragraphs.
+const paragraphRelatedElements = [
+    'P',
+    'H1',
+    'H2',
+    'H3',
+    'H4',
+    'H5',
+    'H6',
+];
+
+/**
+ * Return true if the given node allows "paragraph-related elements".
+ *
+ * @see paragraphRelatedElements
+ * @param {Node} node
+ * @returns {boolean}
+ */
+export function allowsParagraphRelatedElements(node) {
+    return isBlock(node) && !paragraphRelatedElements.includes(node.nodeName);
+}
+
+/**
+ * Take a node and unwrap all of its block contents recursively. All blocks
+ * (except for firstChilds) are preceded by a <br> in order to preserve the line
+ * breaks.
+ *
+ * @param {Node} node
+ */
+export function makeContentsInline(node) {
+    let childIndex = 0;
+    for (const child of node.childNodes) {
+        if (isBlock(child)) {
+            if (childIndex && paragraphRelatedElements.includes(child.nodeName)) {
+                child.before(document.createElement('br'));
+            }
+            for (const grandChild of child.childNodes) {
+                child.before(grandChild);
+                makeContentsInline(grandChild);
+            }
+            child.remove();
+        }
+        childIndex += 1;
+    }
+}
+
 /**
  * Returns an array of url infos for url matched in the given string.
  *