diff --git a/sources/AppBundle/Accounting/Form/QuotationType.php b/sources/AppBundle/Accounting/Form/QuotationType.php
index 01d2a1302..523b8dbc5 100644
--- a/sources/AppBundle/Accounting/Form/QuotationType.php
+++ b/sources/AppBundle/Accounting/Form/QuotationType.php
@@ -151,6 +151,7 @@ public function buildForm(FormBuilderInterface $builder, array $options): void
             'keep_as_list' => true,
             'allow_add' => true,
             'allow_delete' => true,
+            'constraints' => [new Assert\Valid()],
         ]);
 
         if ($options['actionType'] === 'edit') {
diff --git a/sources/AppBundle/Accounting/Model/Invoicing.php b/sources/AppBundle/Accounting/Model/Invoicing.php
index dd5c4fe8d..2914f8a1f 100644
--- a/sources/AppBundle/Accounting/Model/Invoicing.php
+++ b/sources/AppBundle/Accounting/Model/Invoicing.php
@@ -10,7 +10,6 @@
 use CCMBenchmark\Ting\Entity\NotifyProperty;
 use CCMBenchmark\Ting\Entity\NotifyPropertyInterface;
 use DateTime;
-use Symfony\Component\Validator\Constraints as Assert;
 
 class Invoicing implements NotifyPropertyInterface
 {
@@ -40,7 +39,6 @@ class Invoicing implements NotifyPropertyInterface
     private ?DateTime $paymentDate = null;
     private ?InvoicingCurrency $currency = null;
     /** @var InvoicingDetail[] */
-    #[Assert\Valid]
     private array $details = [];
 
     private ?float $price = null;
diff --git a/tests/unit/AppBundle/Accounting/Form/InvoiceTypeTest.php b/tests/unit/AppBundle/Accounting/Form/InvoiceTypeTest.php
new file mode 100644
index 000000000..4cb4a8cc9
--- /dev/null
+++ b/tests/unit/AppBundle/Accounting/Form/InvoiceTypeTest.php
@@ -0,0 +1,134 @@
+<?php
+
+declare(strict_types=1);
+
+namespace AppBundle\Tests\Accounting\Form;
+
+use Afup\Site\Utils\Pays;
+use AppBundle\Accounting\Form\InvoiceType;
+use AppBundle\Accounting\InvoicingPaymentStatus;
+use AppBundle\Accounting\Model\Invoicing;
+use AppBundle\Accounting\Model\InvoicingDetail;
+use PHPUnit\Framework\Attributes\AllowMockObjectsWithoutExpectations;
+use PHPUnit\Framework\Attributes\Test;
+use Symfony\Component\Form\Extension\Validator\ValidatorExtension;
+use Symfony\Component\Form\PreloadedExtension;
+use Symfony\Component\Form\Test\TypeTestCase;
+use Symfony\Component\Validator\Validation;
+
+/**
+ * L'écran facture affiche les lignes en lecture seule : il ne doit valider que ce qu'il
+ * laisse modifier, sans quoi une donnée héritée bloque toute modification de la facture.
+ */
+#[AllowMockObjectsWithoutExpectations] // TypeTestCase mocke l'EventDispatcher en interne
+class InvoiceTypeTest extends TypeTestCase
+{
+    protected function getExtensions(): array
+    {
+        $pays = $this->createMock(Pays::class);
+        $pays->method('obtenirPays')->willReturn(['FR' => 'France']);
+
+        return [
+            new PreloadedExtension([new InvoiceType($pays)], []),
+            // TypeTestCase ne la charge pas, or l'option `constraints` en dépend.
+            new ValidatorExtension(Validation::createValidatorBuilder()->enableAttributeMapping()->getValidator()),
+        ];
+    }
+
+    #[Test]
+    public function uneFacturePeutEtreMarqueePayee(): void
+    {
+        $invoice = $this->newInvoice([$this->detail('SPONSO', 'Sponsoring bronze')]);
+        $form = $this->factory->create(InvoiceType::class, $invoice);
+
+        $form->submit($this->payload());
+
+        self::assertTrue($form->isValid(), (string) $form->getErrors(true, false));
+        self::assertSame(InvoicingPaymentStatus::Payed, $invoice->getPaymentStatus());
+    }
+
+    /**
+     * Le back-office historique créait systématiquement cinq lignes de détail, vides
+     * comprises. Ces lignes ne sont pas éditables depuis l'écran facture : les valider
+     * rendrait ces factures définitivement non modifiables.
+     */
+    #[Test]
+    public function uneFactureAvecDesLignesVidesHeriteesPeutEtreMarqueePayee(): void
+    {
+        $invoice = $this->newInvoice([
+            $this->detail('SPONSO', 'Sponsoring bronze'),
+            $this->detail('', ''),
+            $this->detail('', ''),
+        ]);
+        $form = $this->factory->create(InvoiceType::class, $invoice);
+
+        $form->submit($this->payload());
+
+        self::assertTrue($form->isValid(), (string) $form->getErrors(true, false));
+        self::assertSame(InvoicingPaymentStatus::Payed, $invoice->getPaymentStatus());
+    }
+
+    /**
+     * @return array<string, string>
+     */
+    private function payload(): array
+    {
+        return [
+            'invoiceDate' => '2026-01-15',
+            'company' => 'ACME',
+            'service' => '',
+            'address' => '1 rue du test',
+            'zipcode' => '69000',
+            'city' => 'Lyon',
+            'countryId' => 'FR',
+            'lastname' => '',
+            'firstname' => '',
+            'phone' => '',
+            'email' => 'compta@example.com',
+            'tvaIntra' => '',
+            'refClt1' => '',
+            'refClt2' => '',
+            'refClt3' => '',
+            'observation' => '',
+            'currency' => 'EUR',
+            'quotationNumber' => '2026-001',
+            'invoiceNumber' => '2026-001',
+            'paymentStatus' => (string) InvoicingPaymentStatus::Payed->value,
+            'paymentDate' => '2026-02-01',
+        ];
+    }
+
+    /**
+     * @param list<InvoicingDetail> $details
+     */
+    private function newInvoice(array $details): Invoicing
+    {
+        $invoice = new Invoicing();
+        $invoice->setId(42);
+        $invoice->setCompany('ACME');
+        $invoice->setAddress('1 rue du test');
+        $invoice->setZipcode('69000');
+        $invoice->setCity('Lyon');
+        $invoice->setCountryId('FR');
+        $invoice->setEmail('compta@example.com');
+        $invoice->setQuotationNumber('2026-001');
+        $invoice->setInvoiceNumber('2026-001');
+        $invoice->setInvoiceDate(new \DateTime('2026-01-15'));
+        $invoice->setPaymentStatus(InvoicingPaymentStatus::Waiting);
+        $invoice->setDetails($details);
+
+        return $invoice;
+    }
+
+    private function detail(string $reference, string $designation): InvoicingDetail
+    {
+        $detail = new InvoicingDetail();
+        $detail->setReference($reference);
+        $detail->setDesignation($designation);
+        $detail->setQuantity(0.0);
+        $detail->setUnitPrice(0.0);
+        $detail->setTva(0.0);
+
+        return $detail;
+    }
+}