diff --git a/network-store-client/src/main/java/com/powsybl/network/store/client/RestClient.java b/network-store-client/src/main/java/com/powsybl/network/store/client/RestClient.java
index 044d9da57..6982718d4 100644
--- a/network-store-client/src/main/java/com/powsybl/network/store/client/RestClient.java
+++ b/network-store-client/src/main/java/com/powsybl/network/store/client/RestClient.java
@@ -6,8 +6,8 @@
  */
 package com.powsybl.network.store.client;
 
-import com.powsybl.network.store.model.AbstractTopLevelDocument;
 import com.powsybl.network.store.model.Attributes;
+import com.powsybl.network.store.model.ExtensionAttributes;
 import com.powsybl.network.store.model.IdentifiableAttributes;
 import com.powsybl.network.store.model.Resource;
 import org.springframework.core.ParameterizedTypeReference;
@@ -22,9 +22,16 @@ public interface RestClient {
 
     <T extends IdentifiableAttributes> void createAll(String url, List<Resource<T>> resources, Object... uriVariables);
 
-    <T, D extends AbstractTopLevelDocument<T>> Optional<T> getOne(String target, String url, ParameterizedTypeReference<D> parameterizedTypeReference, Object... uriVariables);
+    <T extends IdentifiableAttributes> Optional<Resource<T>> getOne(String target, String url, Object... uriVariables);
 
-    <T, D extends AbstractTopLevelDocument<T>> List<T> getAll(String target, String url, ParameterizedTypeReference<D> parameterizedTypeReference, Object... uriVariables);
+    /**
+     * Retrieves one extension attributes from the server.
+     * @return {@link ExtensionAttributes} which is a subset of an identifiable resource. The extension attributes can be put in the extensionAttributes
+     * map of an {@link IdentifiableAttributes} or used to load an extension.
+     */
+    Optional<ExtensionAttributes> getOneExtensionAttributes(String url, Object... uriVariables);
+
+    <T extends IdentifiableAttributes> List<Resource<T>> getAll(String target, String url, Object... uriVariables);
 
     <T extends Attributes> void updateAll(String url, List<Resource<T>> resources, Object... uriVariables);
 
diff --git a/network-store-client/src/main/java/com/powsybl/network/store/client/RestClientImpl.java b/network-store-client/src/main/java/com/powsybl/network/store/client/RestClientImpl.java
index 305330f07..db8ced1da 100644
--- a/network-store-client/src/main/java/com/powsybl/network/store/client/RestClientImpl.java
+++ b/network-store-client/src/main/java/com/powsybl/network/store/client/RestClientImpl.java
@@ -90,7 +90,18 @@ public <T extends IdentifiableAttributes> void createAll(String url, List<Resour
     }
 
     @Override
-    public <T, D extends AbstractTopLevelDocument<T>> Optional<T> getOne(String target, String url, ParameterizedTypeReference<D> parameterizedTypeReference, Object... uriVariables) {
+    public <T extends IdentifiableAttributes> Optional<Resource<T>> getOne(String target, String url, Object... uriVariables) {
+        return getOneDocument(target, url, new ParameterizedTypeReference<TopLevelDocument<T>>() {
+        }, uriVariables);
+    }
+
+    @Override
+    public Optional<ExtensionAttributes> getOneExtensionAttributes(String url, Object... uriVariables) {
+        return getOneDocument(null, url, new ParameterizedTypeReference<ExtensionAttributesTopLevelDocument>() {
+        }, uriVariables);
+    }
+
+    public <T, D extends AbstractTopLevelDocument<T>> Optional<T> getOneDocument(String target, String url, ParameterizedTypeReference<D> parameterizedTypeReference, Object... uriVariables) {
         ResponseEntity<D> response = getDocument(url, parameterizedTypeReference, uriVariables);
         if (response.getStatusCode() == HttpStatus.OK) {
             AbstractTopLevelDocument<T> body = getBody(response);
@@ -103,12 +114,13 @@ public <T, D extends AbstractTopLevelDocument<T>> Optional<T> getOne(String targ
     }
 
     @Override
-    public <T, D extends AbstractTopLevelDocument<T>> List<T> getAll(String target, String url, ParameterizedTypeReference<D> parameterizedTypeReference, Object... uriVariables) {
-        ResponseEntity<D> response = getDocument(url, parameterizedTypeReference, uriVariables);
+    public <T extends IdentifiableAttributes> List<Resource<T>> getAll(String target, String url, Object... uriVariables) {
+        ResponseEntity<TopLevelDocument<T>> response = getDocument(url, new ParameterizedTypeReference<>() {
+        }, uriVariables);
         if (response.getStatusCode() != HttpStatus.OK) {
             throw createHttpException(url, "get", response.getStatusCode());
         }
-        AbstractTopLevelDocument<T> body = getBody(response);
+        TopLevelDocument<T> body = getBody(response);
         return body.getData();
     }
 
diff --git a/network-store-client/src/main/java/com/powsybl/network/store/client/RestNetworkStoreClient.java b/network-store-client/src/main/java/com/powsybl/network/store/client/RestNetworkStoreClient.java
index 79a05d9d7..a0c68d986 100644
--- a/network-store-client/src/main/java/com/powsybl/network/store/client/RestNetworkStoreClient.java
+++ b/network-store-client/src/main/java/com/powsybl/network/store/client/RestNetworkStoreClient.java
@@ -98,8 +98,7 @@ private <T extends IdentifiableAttributes> List<Resource<T>> getAll(String targe
             LOGGER.info("Loading {} resources {}", target, UriComponentsBuilder.fromUriString(url).buildAndExpand(uriVariables));
         }
         Stopwatch stopwatch = Stopwatch.createStarted();
-        List<Resource<T>> resourceList = restClient.getAll(target, url, new ParameterizedTypeReference<TopLevelDocument<T>>() {
-        }, uriVariables);
+        List<Resource<T>> resourceList = restClient.getAll(target, url, uriVariables);
         stopwatch.stop();
         LOGGER.info("{} {} resources loaded in {} ms", resourceList.size(), target, stopwatch.elapsed(TimeUnit.MILLISECONDS));
         return resourceList;
@@ -110,8 +109,7 @@ private <T extends IdentifiableAttributes> Optional<Resource<T>> get(String targ
             LOGGER.info("Loading {} resource {}", target, UriComponentsBuilder.fromUriString(url).buildAndExpand(uriVariables));
         }
         Stopwatch stopwatch = Stopwatch.createStarted();
-        Optional<Resource<T>> resource = restClient.getOne(target, url, new ParameterizedTypeReference<TopLevelDocument<T>>() {
-        }, uriVariables);
+        Optional<Resource<T>> resource = restClient.getOne(target, url, uriVariables);
         stopwatch.stop();
         LOGGER.info("{} resource (empty={}) loaded in {} ms", target, resource.isEmpty(), stopwatch.elapsed(TimeUnit.MILLISECONDS));
         return resource;
@@ -120,8 +118,7 @@ private <T extends IdentifiableAttributes> Optional<Resource<T>> get(String targ
     private Optional<ExtensionAttributes> getExtensionAttributes(String urlTemplate, Object... uriVariables) {
         logGetExtensionAttributesUrl(urlTemplate, uriVariables);
         Stopwatch stopwatch = Stopwatch.createStarted();
-        Optional<ExtensionAttributes> extensionAttributes = restClient.getOne(null, urlTemplate, new ParameterizedTypeReference<ExtensionAttributesTopLevelDocument>() {
-        }, uriVariables);
+        Optional<ExtensionAttributes> extensionAttributes = restClient.getOneExtensionAttributes(urlTemplate, uriVariables);
         stopwatch.stop();
         logGetExtensionAttributesTime(extensionAttributes.isPresent() ? 1 : 0, stopwatch.elapsed(TimeUnit.MILLISECONDS));