diff --git a/services/src/main/java/org/keycloak/protocol/oidc/par/endpoints/ParEndpoint.java b/services/src/main/java/org/keycloak/protocol/oidc/par/endpoints/ParEndpoint.java
index 6ba4d19bfe7..b5ae1ab47a9 100644
--- a/services/src/main/java/org/keycloak/protocol/oidc/par/endpoints/ParEndpoint.java
+++ b/services/src/main/java/org/keycloak/protocol/oidc/par/endpoints/ParEndpoint.java
@@ -27,6 +27,7 @@ import org.keycloak.events.EventType;
 import org.keycloak.headers.SecurityHeadersProvider;
 import org.keycloak.models.KeycloakSession;
 import org.keycloak.models.SingleUseObjectProvider;
+import org.keycloak.protocol.oidc.OIDCLoginProtocol;
 import org.keycloak.protocol.oidc.OIDCLoginProtocolService;
 import org.keycloak.protocol.oidc.endpoints.AuthorizationEndpointChecker;
 import org.keycloak.protocol.oidc.endpoints.request.AuthorizationEndpointRequest;
@@ -108,6 +109,9 @@ public class ParEndpoint extends AbstractParEndpoint {
         try {
             authorizationRequest = ParEndpointRequestParserProcessor.parseRequest(event, session, client, decodedFormParameters);
         } catch (Exception e) {
+            if (!decodedFormParameters.containsKey(OIDCLoginProtocol.REQUEST_PARAM)) {
+                throw throwErrorResponseException(OAuthErrorException.INVALID_REQUEST, e.getMessage(), Response.Status.BAD_REQUEST);
+            }
             throw throwErrorResponseException(OAuthErrorException.INVALID_REQUEST_OBJECT, e.getMessage(), Response.Status.BAD_REQUEST);
         }
 
diff --git a/testsuite/integration-arquillian/tests/base/src/test/java/org/keycloak/testsuite/client/FAPI2DPoPTest.java b/testsuite/integration-arquillian/tests/base/src/test/java/org/keycloak/testsuite/client/FAPI2DPoPTest.java
index 385b52590a4..fae68379693 100644
--- a/testsuite/integration-arquillian/tests/base/src/test/java/org/keycloak/testsuite/client/FAPI2DPoPTest.java
+++ b/testsuite/integration-arquillian/tests/base/src/test/java/org/keycloak/testsuite/client/FAPI2DPoPTest.java
@@ -444,7 +444,7 @@ public class FAPI2DPoPTest extends AbstractFAPI2Test {
                 .signedJwt(signedJwt)
                 .send();
         assertEquals(400, pResp.getStatusCode());
-        assertEquals(OAuthErrorException.INVALID_REQUEST_OBJECT, pResp.getError());
+        assertEquals(OAuthErrorException.INVALID_REQUEST, pResp.getError());
 
         // Set request object and correct responseType
         requestObject = createValidRequestObjectForSecureRequestObjectExecutor(clientId);
diff --git a/testsuite/integration-arquillian/tests/base/src/test/java/org/keycloak/testsuite/client/FAPI2Test.java b/testsuite/integration-arquillian/tests/base/src/test/java/org/keycloak/testsuite/client/FAPI2Test.java
index 82f10667845..68cb1dbed91 100644
--- a/testsuite/integration-arquillian/tests/base/src/test/java/org/keycloak/testsuite/client/FAPI2Test.java
+++ b/testsuite/integration-arquillian/tests/base/src/test/java/org/keycloak/testsuite/client/FAPI2Test.java
@@ -335,7 +335,7 @@ public class FAPI2Test extends AbstractFAPITest {
         String signedJwt = createSignedRequestToken(clientId, Algorithm.PS256);
         ParResponse pResp = oauth.pushedAuthorizationRequest().nonce("123456").signedJwt(signedJwt).send();
         assertEquals(400, pResp.getStatusCode());
-        assertEquals(OAuthErrorException.INVALID_REQUEST_OBJECT, pResp.getError());
+        assertEquals(OAuthErrorException.INVALID_REQUEST, pResp.getError());
 
         // Set request object and correct responseType
         requestObject = createValidRequestObjectForSecureRequestObjectExecutor(clientId);
diff --git a/testsuite/integration-arquillian/tests/base/src/test/java/org/keycloak/testsuite/oauth/par/ParTest.java b/testsuite/integration-arquillian/tests/base/src/test/java/org/keycloak/testsuite/oauth/par/ParTest.java
index e682e703896..3e4c7337c74 100644
--- a/testsuite/integration-arquillian/tests/base/src/test/java/org/keycloak/testsuite/oauth/par/ParTest.java
+++ b/testsuite/integration-arquillian/tests/base/src/test/java/org/keycloak/testsuite/oauth/par/ParTest.java
@@ -1010,7 +1010,7 @@ public class ParTest extends AbstractClientPoliciesTest {
         oauth.redirectUri(CLIENT_REDIRECT_URI);
         ParResponse pResp = oauth.doPushedAuthorizationRequest();
         assertEquals(400, pResp.getStatusCode());
-        assertEquals(OAuthErrorException.INVALID_REQUEST_OBJECT, pResp.getError());
+        assertEquals(OAuthErrorException.INVALID_REQUEST, pResp.getError());
     }
 
     // PAR including invalid redirect_uri