diff --git a/app/entreprises/forms.py b/app/entreprises/forms.py
index f7fd62816..d2f3762b6 100644
--- a/app/entreprises/forms.py
+++ b/app/entreprises/forms.py
@@ -3,10 +3,10 @@ from markupsafe import Markup
 from flask.app import Flask
 import requests, re
 from flask_wtf import FlaskForm
-from wtforms import StringField, SubmitField, TextAreaField, SelectField, FileField
+from wtforms import StringField, SubmitField, TextAreaField, SelectField, FileField, HiddenField
 from wtforms.fields.html5 import EmailField, DateField
 from wtforms.validators import ValidationError, DataRequired, Email
-from app.entreprises.models import Entreprise
+from app.entreprises.models import Entreprise, EntrepriseContact
 from app.models import Identite
 from app.auth.models import User
 from app.scodoc import sco_etud
@@ -71,8 +71,27 @@ class ContactCreationForm(FlaskForm):
     prenom = StringField("Prénom", validators=[DataRequired(message=DATA_REQUIRED_ERROR_MESSAGE)])
     telephone = StringField("Téléphone", validators=[DataRequired(message=DATA_REQUIRED_ERROR_MESSAGE)])
     mail = EmailField("Mail", validators=[DataRequired(message=DATA_REQUIRED_ERROR_MESSAGE), Email(message="Adresse e-mail invalide")])
+    hidden_entreprise_id = HiddenField()
     submit = SubmitField("Envoyer")
 
+    def validate(self):
+        rv = FlaskForm.validate(self)
+        if not rv:
+            return False
+        
+        contact = EntrepriseContact.query.filter_by(
+            entreprise_id = self.hidden_entreprise_id.data,
+            nom = self.nom.data,
+            prenom = self.prenom.data
+        ).first()
+
+        if contact is not None:
+            self.nom.errors.append("Ce contact existe déjà (même nom et prénom)")
+            self.prenom.errors.append("")
+            return False
+
+        return True
+
 class ContactModificationForm(FlaskForm):
     nom = StringField("Nom", validators=[DataRequired(message=DATA_REQUIRED_ERROR_MESSAGE)])
     prenom = StringField("Prénom", validators=[DataRequired(message=DATA_REQUIRED_ERROR_MESSAGE)])
diff --git a/app/entreprises/routes.py b/app/entreprises/routes.py
index 4808cbebe..1791199e5 100644
--- a/app/entreprises/routes.py
+++ b/app/entreprises/routes.py
@@ -238,7 +238,7 @@ def delete_offre(id):
 @bp.route("/add_contact/<id>", methods=["GET", "POST"])
 def add_contact(id):
     entreprise = Entreprise.query.filter_by(id=id).first_or_404()
-    form = ContactCreationForm()
+    form = ContactCreationForm(hidden_entreprise_id=entreprise.id)
     if form.validate_on_submit():
         contact = EntrepriseContact(
             entreprise_id=entreprise.id,
diff --git a/app/templates/entreprises/ajout_entreprise.html b/app/templates/entreprises/ajout_entreprise.html
index 76a9619e4..6b0ba311e 100644
--- a/app/templates/entreprises/ajout_entreprise.html
+++ b/app/templates/entreprises/ajout_entreprise.html
@@ -12,6 +12,9 @@
     <br>
     <div class="row">
         <div class="col-md-4">
+            <p>
+                Les champs s'autocomplète selon le SIRET
+            </p>
             {{ wtf.quick_form(form, novalidate=True) }}
         </div>
     </div>