diff --git a/metafacture-commons/src/main/java/org/metafacture/commons/tries/SimpleRegexTrie.java b/metafacture-commons/src/main/java/org/metafacture/commons/tries/SimpleRegexTrie.java
index 7cd49a7b5..2284eeb87 100644
--- a/metafacture-commons/src/main/java/org/metafacture/commons/tries/SimpleRegexTrie.java
+++ b/metafacture-commons/src/main/java/org/metafacture/commons/tries/SimpleRegexTrie.java
@@ -28,8 +28,11 @@
  */
 public class SimpleRegexTrie<P> {
 
+    // Non-empty character class, containing non-[] characters, e.g.
+    // matches: `lit-[A]`, `lit-[AB]`, does not match: `a[].1`, `a[].1.b[].1`
+    public static final String SIMPLE_CHARACTER_CLASS = ".*\\[[^\\[\\]]+\\].*";
+
     private final WildcardTrie<P> trie;
-    public static final String SIMPLE_CHARACTER_CLASS = "\\[.+\\]";
 
     public SimpleRegexTrie() {
         trie = new WildcardTrie<P>();
@@ -43,7 +46,7 @@ public SimpleRegexTrie() {
      * @param value value to associate with the key pattern
      */
     public void put(final String keys, final P value) {
-        if (keys.matches(".*" + SIMPLE_CHARACTER_CLASS + ".*")) {
+        if (keys.matches(SIMPLE_CHARACTER_CLASS)) {
             int charClassStart = keys.indexOf('[', 0);
             final int charClassEnd = keys.indexOf(']', 1);
             String begin = keys.substring(0, charClassStart);
diff --git a/metafacture-commons/src/test/java/org/metafacture/commons/tries/SimpleRegexTrieTest.java b/metafacture-commons/src/test/java/org/metafacture/commons/tries/SimpleRegexTrieTest.java
index 6c501c76f..65e771ca4 100644
--- a/metafacture-commons/src/test/java/org/metafacture/commons/tries/SimpleRegexTrieTest.java
+++ b/metafacture-commons/src/test/java/org/metafacture/commons/tries/SimpleRegexTrieTest.java
@@ -41,7 +41,8 @@ public void testWithSimpleCharacterClass() {
     public void testWithEmptyCharacterClass() {
         final SimpleRegexTrie<String> trie = new SimpleRegexTrie<String>();
         // Should not be treated as character class (used for JSON arrays):
-        trie.put("a[].1", "value");
-        assertTrue("Expecting to find: a[].1", trie.get("a[].1").size() == 1);
+        final String key = "a[].1.b[].1";
+        trie.put(key, "value");
+        assertTrue("Expecting to find: " + key, trie.get(key).size() == 1);
     }
 }