diff --git a/src/main/asciidoc/reference/reactive-mongo-repositories.adoc b/src/main/asciidoc/reference/reactive-mongo-repositories.adoc
index a8ab6dfed..0f7db07d2 100644
--- a/src/main/asciidoc/reference/reactive-mongo-repositories.adoc
+++ b/src/main/asciidoc/reference/reactive-mongo-repositories.adoc
@@ -47,7 +47,7 @@ Note that the entity defined in the preceding example has a property named `id`
 ====
 [source]
 ----
-public interface ReactivePersonRepository extends ReactiveSortingRepository<Person, Long> {
+public interface ReactivePersonRepository extends ReactiveSortingRepository<Person, String> {
 
   Flux<Person> findByFirstname(String firstname);                                   <1>