diff --git a/apptax/taxonomie/models.py b/apptax/taxonomie/models.py
index 9b16f9cc..090bf105 100644
--- a/apptax/taxonomie/models.py
+++ b/apptax/taxonomie/models.py
@@ -230,6 +230,9 @@ def where_params(cls, filters=None, *, query):
                 query = query.filter(col.ilike(value + "%"))
         return query
 
+    def __le__(self, other):
+        return self.tree <= other.tree
+
 
 @serializable
 class BibListes(db.Model):
@@ -546,6 +549,11 @@ class TaxrefTree(db.Model):
     taxref = db.relationship(Taxref, backref=backref("tree", uselist=False))
     path = db.Column(db.String, nullable=False)
 
+    def __le__(self, other):
+        # self <= other means taxon other is the same or a parent of self
+        p1, p2 = self.path.split("."), other.path.split(".")
+        return len(p1) >= len(p2) and p1[: len(p2)] == p2
+
 
 # Taxref deffered properties
 
diff --git a/apptax/tests/test_models.py b/apptax/tests/test_models.py
new file mode 100644
index 00000000..b59ab1e1
--- /dev/null
+++ b/apptax/tests/test_models.py
@@ -0,0 +1,46 @@
+import pytest
+import sqlalchemy as sa
+
+from .fixtures import *
+from apptax.taxonomie.models import Taxref, TaxrefTree
+
+
+@pytest.mark.usefixtures("client_class", "temporary_transaction")
+class TestModels:
+    def test_taxref_tree_comparison(self):
+        animalia = db.session.execute(
+            sa.select(TaxrefTree).where(TaxrefTree.cd_nom == 183716)
+        ).scalar_one()
+        capra_ibex = db.session.execute(
+            sa.select(TaxrefTree).where(TaxrefTree.cd_nom == 61098)
+        ).scalar_one()
+        cinnamon = db.session.execute(
+            sa.select(TaxrefTree).where(TaxrefTree.cd_nom == 706584)
+        ).scalar_one()
+
+        assert animalia <= animalia
+        assert capra_ibex <= animalia
+        assert not animalia <= capra_ibex
+        assert not cinnamon <= animalia
+        assert not animalia <= cinnamon
+        assert not cinnamon <= capra_ibex
+        assert not capra_ibex <= cinnamon
+
+    def test_taxref_comparison(self):
+        animalia = db.session.execute(
+            sa.select(Taxref).where(Taxref.cd_nom == 183716)
+        ).scalar_one()
+        capra_ibex = db.session.execute(
+            sa.select(Taxref).where(Taxref.cd_nom == 61098)
+        ).scalar_one()
+        cinnamon = db.session.execute(
+            sa.select(Taxref).where(Taxref.cd_nom == 706584)
+        ).scalar_one()
+
+        assert animalia <= animalia
+        assert capra_ibex <= animalia
+        assert not animalia <= capra_ibex
+        assert not cinnamon <= animalia
+        assert not animalia <= cinnamon
+        assert not cinnamon <= capra_ibex
+        assert not capra_ibex <= cinnamon