diff --git a/odoo/fields.py b/odoo/fields.py
index a311a99385a..6b76a8a05d7 100644
--- a/odoo/fields.py
+++ b/odoo/fields.py
@@ -25,10 +25,11 @@ import pytz
 from markupsafe import Markup
 from psycopg2.extras import Json as PsycopgJson, execute_values
 from psycopg2.sql import SQL, Identifier
-from difflib import get_close_matches
+from difflib import get_close_matches, unified_diff
 from hashlib import sha256
 
 from .models import check_property_field_value_name
+from .netsvc import ColoredFormatter, GREEN, RED, DEFAULT, COLOR_PATTERN
 from .tools import (
     float_repr, float_round, float_compare, float_is_zero, human_size,
     pg_varchar, ustr, OrderedSet, pycompat, sql, date_utils, unique,
@@ -2024,6 +2025,22 @@ class Html(_String):
                     # sanitized. It means that someone who was part of a group
                     # allowing to bypass the sanitation saved that field
                     # previously.
+
+                    diff = unified_diff(
+                        original_value_sanitized.splitlines(),
+                        original_value_normalized.splitlines(),
+                    )
+
+                    with_colors = isinstance(logging.getLogger().handlers[0].formatter, ColoredFormatter)
+                    diff_str = f'The field ({record._description}, {self.string}) will not be editable:\n'
+                    for line in list(diff)[2:]:
+                        if with_colors:
+                            color = {'-': RED, '+': GREEN}.get(line[:1], DEFAULT)
+                            diff_str += COLOR_PATTERN % (30 + color, 40 + DEFAULT, line.rstrip() + "\n")
+                        else:
+                            diff_str += line.rstrip() + '\n'
+                    _logger.info(diff_str)
+
                     raise UserError(_(
                         "The field value you're saving (%s %s) includes content that is "
                         "restricted for security reasons. It is possible that someone "