diff --git a/lib/GaletteObjectsLend/Controllers/Crud/ObjectsController.php b/lib/GaletteObjectsLend/Controllers/Crud/ObjectsController.php
index 1177705..c0aeccc 100644
--- a/lib/GaletteObjectsLend/Controllers/Crud/ObjectsController.php
+++ b/lib/GaletteObjectsLend/Controllers/Crud/ObjectsController.php
@@ -778,7 +778,7 @@ public function doReturn(Request $request, Response $response, int $id): Respons
         $object = $service->getObject($id);
 
         try {
-            $service->giveBack($object, (int)($post['status'] ?? 0));
+            $service->giveBack($object, (int)($post['status'] ?? 0), trim($post['comments'] ?? ''));
         } catch (LendException $e) {
             $this->flash->addMessage('error_detected', $e->getMessage());
             return $response
diff --git a/lib/GaletteObjectsLend/Controllers/MainController.php b/lib/GaletteObjectsLend/Controllers/MainController.php
index 658ba2d..7dc69d3 100644
--- a/lib/GaletteObjectsLend/Controllers/MainController.php
+++ b/lib/GaletteObjectsLend/Controllers/MainController.php
@@ -45,7 +45,8 @@ public function preferences(Request $request, Response $response): Response
 
         $params = [
             'page_title'    => _T('ObjectsLend preferences', 'objectslend'),
-            'type_cotis_options'        => $ctypes->getList(),
+            //a rent is not a membership fee
+            'type_cotis_options'        => $ctypes->getList(false),
             'lendsprefs'    => (new LendPreferences($this->preferences))->toArray(),
             'sample_data'   => !(new SampleData($this->zdb))->hasObjects()
         ];
@@ -75,6 +76,18 @@ public function storePreferences(Request $request, Response $response): Response
 
         $stored = true;
         $errors = [];
+
+        //a membership fee would extend the membership, and needs an end date
+        $type_id = $post[LendPreferences::GENERATED_CONTRIBUTION_TYPE_ID] ?? null;
+        if (
+            isset($post[LendPreferences::AUTO_GENERATE_CONTRIBUTION])
+            && !isset((new ContributionsTypes($this->zdb))->getList(false)[(int)$type_id])
+        ) {
+            $stored = false;
+            $errors[] = _T("Generated contributions must be of a donation type.", "objectslend");
+            unset($post[LendPreferences::GENERATED_CONTRIBUTION_TYPE_ID]);
+        }
+
         foreach (array_keys(LendPreferences::getSchema()) as $name) {
             if (isset($booleans[$name])) {
                 $value = (int)isset($post[$name]);
diff --git a/lib/GaletteObjectsLend/Entity/LendRent.php b/lib/GaletteObjectsLend/Entity/LendRent.php
index 3f0dd6e..50c83ac 100644
--- a/lib/GaletteObjectsLend/Entity/LendRent.php
+++ b/lib/GaletteObjectsLend/Entity/LendRent.php
@@ -231,13 +231,13 @@ public function getComments(): string
     }
 
     /**
-     * Set comments
+     * Set comments, cut to the column size
      *
      * @param string $comments Comments
      */
     public function setComments(string $comments): self
     {
-        $this->comments = $comments;
+        $this->comments = mb_substr($comments, 0, 200);
         return $this;
     }
 
diff --git a/lib/GaletteObjectsLend/LendService.php b/lib/GaletteObjectsLend/LendService.php
index 9ff36f5..f20a3a9 100644
--- a/lib/GaletteObjectsLend/LendService.php
+++ b/lib/GaletteObjectsLend/LendService.php
@@ -189,10 +189,11 @@ public function take(
      *
      * @param LendObject $object    Object, loaded with getObject()
      * @param int        $status_id In stock status
+     * @param string     $comments  Comment on the closed rent
      *
      * @throws LendException
      */
-    public function giveBack(LendObject $object, int $status_id): LendRent
+    public function giveBack(LendObject $object, int $status_id, string $comments = ''): LendRent
     {
         if (!$this->canGiveBack($object)) {
             $this->refuse(
@@ -214,7 +215,7 @@ public function giveBack(LendObject $object, int $status_id): LendRent
         }
 
         return $this->inTransaction(
-            fn() => $this->openRent($object, $status_id, null, '')
+            fn() => $this->openRent($object, $status_id, null, $comments)
         );
     }
 
@@ -378,6 +379,20 @@ private function storeContribution(
         float $amount,
         ?int $payment_type
     ): Contribution {
+        //a membership fee would extend the membership, and needs an end date
+        $type_id = $this->lendsprefs->getContributionTypeId();
+        $ctype = new ContributionsTypes($this->zdb);
+        if (!$ctype->load($type_id) || $ctype->isExtension()) {
+            Analog::log(
+                'Unable to generate contribution for object #' . $object->getId()
+                . ': contribution type #' . $type_id . ' is not a donation one.',
+                Analog::ERROR
+            );
+            throw new LendException(
+                _T("Generated contributions must be of a donation type, check plugin preferences.", "objectslend")
+            );
+        }
+
         $info = str_replace(
             [
                 '{NAME}',
@@ -402,7 +417,7 @@ private function storeContribution(
 
         $values = [
             'montant_cotis'         => $amount,
-            ContributionsTypes::PK  => $this->lendsprefs->getContributionTypeId(),
+            ContributionsTypes::PK  => $type_id,
             'date_enreg'            => date("Y-m-d"),
             'date_debut_cotis'      => date("Y-m-d"),
             'type_paiement_cotis'   => $payment_type,
diff --git a/tests/GaletteObjectsLend/Controllers/tests/units/MainController.php b/tests/GaletteObjectsLend/Controllers/tests/units/MainController.php
index a9d26c1..c8c42e6 100644
--- a/tests/GaletteObjectsLend/Controllers/tests/units/MainController.php
+++ b/tests/GaletteObjectsLend/Controllers/tests/units/MainController.php
@@ -123,6 +123,37 @@ public function testStoreInvalidPreference(): void
         $this->flash_data = [];
     }
 
+    /**
+     * Generated contributions cannot be membership fees
+     */
+    public function testStoreMembershipFeeContributionType(): void
+    {
+        $this->logSuperAdmin();
+        $this->assertTrue($this->preferences->setValue(LendPreferences::GENERATED_CONTRIBUTION_TYPE_ID, 5, $this->login));
+
+        //only donation types are offered
+        $test_response = $this->app->handle($this->createRequest(route_name: 'objectslend_preferences'));
+        $body = (string)$test_response->getBody();
+        $this->assertStringContainsString('data-value="5"', $body);
+        $this->assertStringNotContainsString('data-value="1"', $body);
+
+        $request = $this->createRequest(route_name: 'store_objectlend_preferences', method: 'POST')
+            ->withParsedBody([
+                LendPreferences::AUTO_GENERATE_CONTRIBUTION => '1',
+                LendPreferences::GENERATED_CONTRIBUTION_TYPE_ID => '1',
+                LendPreferences::THUMB_MAX_WIDTH => '210',
+            ]);
+        $test_response = $this->app->handle($request);
+        $this->assertSame(302, $test_response->getStatusCode());
+        $this->expectFlashData(['error_detected' => ['Generated contributions must be of a donation type.']]);
+
+        $this->preferences->load();
+        $lendsprefs = new LendPreferences($this->preferences);
+        $this->assertSame(5, $lendsprefs->getContributionTypeId());
+        //other values are stored
+        $this->assertSame(210, $lendsprefs->getThumbWidth());
+    }
+
     /**
      * Preferences are for admins only
      */
diff --git a/tests/GaletteObjectsLend/Controllers/tests/units/ObjectsController.php b/tests/GaletteObjectsLend/Controllers/tests/units/ObjectsController.php
index b9695de..c0995e0 100644
--- a/tests/GaletteObjectsLend/Controllers/tests/units/ObjectsController.php
+++ b/tests/GaletteObjectsLend/Controllers/tests/units/ObjectsController.php
@@ -374,6 +374,27 @@ public function testMemberReturnOwnObject(): void
         $this->assertCount(2, $this->getRents());
     }
 
+    /**
+     * Comment of the return form goes on the closed rent, cut to its column size
+     */
+    public function testReturnComments(): void
+    {
+        $this->setPrefs(true);
+        $this->logSuperAdmin();
+        $this->lendObject($this->getMemberOne()->id);
+
+        $test_response = $this->app->handle($this->returnRequest(['comments' => ' Back, all good ']));
+        $this->assertSame(301, $test_response->getStatusCode());
+        $closed = array_values(array_filter($this->getRents(), fn($rent) => $rent->getDateEnd() !== ''));
+        $this->assertCount(1, $closed);
+        $this->assertSame('Back, all good', $closed[0]->getComments());
+
+        $this->lendObject($this->getMemberOne()->id);
+        $this->app->handle($this->returnRequest(['comments' => str_repeat('é', 250)]));
+        $comments = array_map(fn($rent) => $rent->getComments(), $this->getRents());
+        $this->assertContains(str_repeat('é', 200), $comments);
+    }
+
     /**
      * Giving back requires an "in stock" status, and a lent object
      */
diff --git a/tests/GaletteObjectsLend/tests/units/LendService.php b/tests/GaletteObjectsLend/tests/units/LendService.php
index 60e0ed8..3bae95c 100644
--- a/tests/GaletteObjectsLend/tests/units/LendService.php
+++ b/tests/GaletteObjectsLend/tests/units/LendService.php
@@ -183,6 +183,39 @@ public function testTakeRollsBackOnContributionError(): void
         $this->assertTrue($service->isAvailable($object));
     }
 
+    /**
+     * Test nothing is stored when generated contribution would be a membership fee
+     */
+    public function testTakeRefusesMembershipFeeContributionType(): void
+    {
+        $this->assertTrue($this->preferences->setValue(LendPreferences::GENERATED_CONTRIBUTION_TYPE_ID, 1, $this->login));
+        $member = $this->getMemberOne();
+        $this->logSuperAdmin();
+        $service = $this->getService();
+
+        try {
+            $service->take(
+                $service->getObject($this->object_id),
+                $this->lent_status,
+                member_id: $member->id
+            );
+            $this->fail('Take should have failed');
+        } catch (LendException $e) {
+            $this->assertSame(
+                'Generated contributions must be of a donation type, check plugin preferences.',
+                $e->getMessage()
+            );
+        }
+        $this->expectLogEntry(
+            Analog::ERROR,
+            'Unable to generate contribution for object #' . $this->object_id . ': contribution type #1 is not a donation one.'
+        );
+
+        $this->assertSame(0, $this->countContributions());
+        $this->assertCount(0, (new \GaletteObjectsLend\Repository\Rents($this->zdb))->getForObject($this->object_id));
+        $this->assertTrue($service->isAvailable($service->getObject($this->object_id)));
+    }
+
     /**
      * Test status change refuses unknown and inactive statuses
      */