diff --git a/esmvalcore/cmor/_fixes/cmip6/cnrm_cm6_1.py b/esmvalcore/cmor/_fixes/cmip6/cnrm_cm6_1.py
index f2815d9ea5..4d634ef820 100644
--- a/esmvalcore/cmor/_fixes/cmip6/cnrm_cm6_1.py
+++ b/esmvalcore/cmor/_fixes/cmip6/cnrm_cm6_1.py
@@ -104,4 +104,17 @@ def fix_metadata(self, cubes):
 
 Cli = Cl
 
+
 Clw = Cl
+
+
+class O3(Cl):
+    """Fixes of ozone variable (mip: AERmon only)."""
+
+    def fix_metadata(self, cubes):
+        for cube in cubes:
+            if "table_id" in cube.attributes:
+                if cube.attributes["table_id"] == "AERmon":
+                    cubes = Cl.fix_metadata(self, cubes)
+                    break
+        return cubes
diff --git a/esmvalcore/cmor/_fixes/cmip6/cnrm_esm2_1.py b/esmvalcore/cmor/_fixes/cmip6/cnrm_esm2_1.py
index 8eb9aafe6c..80082da49c 100644
--- a/esmvalcore/cmor/_fixes/cmip6/cnrm_esm2_1.py
+++ b/esmvalcore/cmor/_fixes/cmip6/cnrm_esm2_1.py
@@ -1,5 +1,6 @@
 """Fixes for CNRM-ESM2-1 model."""
 
+from .cnrm_cm6_1 import O3 as BaseO3  # noqa: N811
 from .cnrm_cm6_1 import Cl as BaseCl
 from .cnrm_cm6_1 import Clcalipso as BaseClcalipso
 from .cnrm_cm6_1 import Cli as BaseCli
@@ -18,4 +19,7 @@
 Clw = BaseClw
 
 
+O3 = BaseO3
+
+
 Omon = BaseOmon
diff --git a/tests/integration/cmor/_fixes/cmip6/test_cnrm_cm6_1.py b/tests/integration/cmor/_fixes/cmip6/test_cnrm_cm6_1.py
index 50785ef4e8..849a5140cf 100644
--- a/tests/integration/cmor/_fixes/cmip6/test_cnrm_cm6_1.py
+++ b/tests/integration/cmor/_fixes/cmip6/test_cnrm_cm6_1.py
@@ -5,6 +5,7 @@
 import pytest
 
 from esmvalcore.cmor._fixes.cmip6.cnrm_cm6_1 import (
+    O3,
     Cl,
     Clcalipso,
     Cli,
@@ -154,3 +155,25 @@ def test_get_thetao_fix():
     """Test getting of fix."""
     fix = Fix.get_fixes("CMIP6", "CNRM-CM6-1", "Omon", "thetao")
     assert fix == [Omon(None), GenericFix(None)]
+
+
+def test_o3_fix_metadata(test_data_path):
+    """Test fix for ``o3`` from mip: AERmon."""
+    nc_path = test_data_path / "cnrm_cm6_1_cl.nc"
+    cubes = iris.load(str(nc_path))
+    # change cl cube from test data to an o3 cube
+    # (reusing vertical hybrid coordinates for testing)
+    o3_cube = cubes.extract_cube("cloud_area_fraction_in_atmosphere_layer")
+    o3_cube.long_name = "Mole Fraction of O3"
+    o3_cube.standard_name = "mole_fraction_of_ozone_in_air"
+    o3_cube.units = "mol mol-1"
+    o3_cube.attributes["table_id"] = "AERmon"
+    o3_cube.var_name = "o3"
+    # test o3 fix_metadata
+    vardef = get_var_info("CMIP6", "AERmon", "o3")
+    fix = O3(vardef)
+    fixed_cubes = fix.fix_metadata(cubes)
+    # make sure the fixed cube has a coordinate "air_pressure"
+    cube = fixed_cubes.extract_cube("mole_fraction_of_ozone_in_air")
+    air_pressure_coord = cube.coord("air_pressure")
+    assert air_pressure_coord.points is not None