diff --git a/locator/network_topology_strategy.cc b/locator/network_topology_strategy.cc
index 6d9e05a5aa..61b685d336 100644
--- a/locator/network_topology_strategy.cc
+++ b/locator/network_topology_strategy.cc
@@ -58,9 +58,12 @@ network_topology_strategy::network_topology_strategy(replication_strategy_params
         }
 
         if (boost::iequals(key, "replication_factor")) {
-            throw exceptions::configuration_exception(
-                "replication_factor is an option for SimpleStrategy, not "
-                "NetworkTopologyStrategy");
+            if (boost::equals(key, "replication_factor")) {
+                on_internal_error(rslogger, "replication_factor should have been replaced with a DC:RF mapping by now");
+            } else {
+                throw exceptions::configuration_exception(format(
+                "'{}' is not a valid option, did you mean (lowercase) 'replication_factor'?", key));
+            }
         }
 
         auto rf = parse_replication_factor(val);
@@ -274,9 +277,8 @@ void network_topology_strategy::validate_options(const gms::feature_service& fs)
     validate_tablet_options(*this, fs, _config_options);
     for (auto& c : _config_options) {
         if (c.first == sstring("replication_factor")) {
-            throw exceptions::configuration_exception(
-                "replication_factor is an option for simple_strategy, not "
-                "network_topology_strategy");
+            on_internal_error(rslogger, format("'replication_factor' tag should be unrolled into a list of DC:RF by now."
+                                               "_config_options:{}", _config_options));
         }
         parse_replication_factor(c.second);
     }
diff --git a/test/cqlpy/test_keyspace.py b/test/cqlpy/test_keyspace.py
index be5f0b4672..2c72bb4d84 100644
--- a/test/cqlpy/test_keyspace.py
+++ b/test/cqlpy/test_keyspace.py
@@ -95,6 +95,19 @@ def test_create_keyspace_double_with(cql):
     with pytest.raises(SyntaxException):
         cql.execute('CREATE KEYSPACE ks WITH WITH DURABLE_WRITES = true')
 
+# Scylla accepts 'replication_factor' in CREATE KEYSPACE statement,
+# but while CQL syntax is case-insensitive, tags within json are case-sensitive,
+# hence anything else than the lowercase 'replication_factor' should be rejected.
+# Reproduces #15336
+def test_create_keyspace_with_case_sensitive_replication_factor_tag(cql):
+    ks = unique_name()
+    # lowercase 'replication_factor' should be accepted
+    with new_test_keyspace(cql, "WITH REPLICATION = { 'class' : 'NetworkTopologyStrategy', 'replication_factor' : 3 }"):
+        pass
+    # 'replication_factor' in any other case than the lowercase should be rejected
+    with pytest.raises(ConfigurationException):
+        cql.execute(f"CREATE KEYSPACE {ks} WITH REPLICATION = {{ 'class' : 'NetworkTopologyStrategy', 'Replication_factor' : 3 }}")
+
 # Test trying a non-existent keyspace - with or without the IF EXISTS flag.
 # This test demonstrates a change of the exception produced between Cassandra 4.0
 # and earlier versions (with Scylla behaving like the earlier versions).