diff --git a/agreement/models/agreement_appendix.py b/agreement/models/agreement_appendix.py
index 8699d5793..03ff83372 100644
--- a/agreement/models/agreement_appendix.py
+++ b/agreement/models/agreement_appendix.py
@@ -51,7 +51,7 @@ class AgreementAppendix(models.Model):
 
     @api.onchange('field_id')
     def onchange_sub_object_id(self):
-        if self.field_id:
+        if self.field_id and self.field_id.relation:
             self.sub_object_id = self.env['ir.model'].search(
                 [('model', '=', self.field_id.relation)])[0]
 
diff --git a/agreement/models/agreement_clause.py b/agreement/models/agreement_clause.py
index 00651f984..fd3e979d2 100644
--- a/agreement/models/agreement_clause.py
+++ b/agreement/models/agreement_clause.py
@@ -60,7 +60,7 @@ class AgreementClause(models.Model):
 
     @api.onchange('field_id')
     def onchange_sub_object_id(self):
-        if self.field_id:
+        if self.field_id and self.field_id.relation:
             self.sub_object_id = self.env['ir.model'].search(
                 [('model', '=', self.field_id.relation)])[0]
 
diff --git a/agreement/models/agreement_recital.py b/agreement/models/agreement_recital.py
index c466f45d2..ea4243103 100644
--- a/agreement/models/agreement_recital.py
+++ b/agreement/models/agreement_recital.py
@@ -52,7 +52,7 @@ class AgreementRecital(models.Model):
 
     @api.onchange('field_id')
     def onchange_sub_object_id(self):
-        if self.field_id:
+        if self.field_id and self.field_id.relation:
             self.sub_object_id = self.env['ir.model'].search(
                 [('model', '=', self.field_id.relation)])[0]
 
diff --git a/agreement/models/agreement_section.py b/agreement/models/agreement_section.py
index 2ee345c6c..fe8e46d73 100644
--- a/agreement/models/agreement_section.py
+++ b/agreement/models/agreement_section.py
@@ -51,7 +51,7 @@ class AgreementSection(models.Model):
 
     @api.onchange('field_id')
     def onchange_sub_object_id(self):
-        if self.field_id:
+        if self.field_id and self.field_id.relation:
             self.sub_object_id = self.env['ir.model'].search(
                 [('model', '=', self.field_id.relation)])[0]