diff --git a/CHANGELOG.md b/CHANGELOG.md
index 106aadd..60a12df 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -12,6 +12,9 @@
   - Short forms for determiners, adjectives, pronouns: `eine(n)`, `gute:r`, `ihm/r`, `diese(r)`, `ein(e)`
 * Added `de_old` German tokenizer variant without gender-sensitive rules
   (use `-l de_old` to split forms like `Nutzer:in` into separate tokens)
+* Fixed thousands separators not being handled consistently (issue #135):
+  - Apostrophe `'` (Swiss format: `1'000'000`)
+  - Thin space U+2009 and narrow no-break space U+202F
 
 ## 2.3.1 [2026-01-28]
 
diff --git a/src/main/jpc/jflex/de/ids_mannheim/korap/tokenizer/DerekoDfaTokenizer.jflex b/src/main/jpc/jflex/de/ids_mannheim/korap/tokenizer/DerekoDfaTokenizer.jflex
index 1d93e6f..0b9cbb8 100644
--- a/src/main/jpc/jflex/de/ids_mannheim/korap/tokenizer/DerekoDfaTokenizer.jflex
+++ b/src/main/jpc/jflex/de/ids_mannheim/korap/tokenizer/DerekoDfaTokenizer.jflex
@@ -663,12 +663,17 @@
 
 // floating point, serial, model numbers, ip addresses, etc.
 // every other segment must have at least one digit
+// THOUSANDS_SEP for thousands separators: apostrophe (Swiss) and thin/narrow no-break space (issue #135)
+THOUSANDS_SEP = ("'"|"'"|[\u2009\u202F])
+
 NUM        = ({ALPHANUM} {P} {HAS_DIGIT}
            | {HAS_DIGIT} {P} {ALPHANUM}
            | {ALPHANUM} ({P} {HAS_DIGIT} {P} {ALPHANUM})+
            | {HAS_DIGIT} ({P} {ALPHANUM} {P} {HAS_DIGIT})+
            | {ALPHANUM} {P} {HAS_DIGIT} ({P} {ALPHANUM} {P} {HAS_DIGIT})+
-           | {HAS_DIGIT} {P} {ALPHANUM} ({P} {HAS_DIGIT} {P} {ALPHANUM})+)
+           | {HAS_DIGIT} {P} {ALPHANUM} ({P} {HAS_DIGIT} {P} {ALPHANUM})+
+           | {HAS_DIGIT} ({THOUSANDS_SEP} {HAS_DIGIT})+
+           | {HAS_DIGIT} ({THOUSANDS_SEP} {HAS_DIGIT})+ {P} {HAS_DIGIT})
 
 
 /* floating point literals */
@@ -682,6 +687,7 @@
 // punctuation
 P	         = ("_"|"-"|"."|",")|{SLASH}
 
+
 Q = [’\'`]
 
 PUNCT = ({P}|{Q}|[?!@#$%\^&*_:;\]\[\"»«\202\204\206\207\213\221\222\223\224\225\226\227\233])
diff --git a/src/test/java/de/ids_mannheim/korap/tokenizer/TokenizerTest.java b/src/test/java/de/ids_mannheim/korap/tokenizer/TokenizerTest.java
index b0ee8c3..11b4938 100644
--- a/src/test/java/de/ids_mannheim/korap/tokenizer/TokenizerTest.java
+++ b/src/test/java/de/ids_mannheim/korap/tokenizer/TokenizerTest.java
@@ -1215,4 +1215,55 @@
         assertEquals("!", tokens[2]);
         assertEquals(3, tokens.length);
     }
+
+    // Regression test for https://github.com/KorAP/KorAP-Tokenizer/issues/135
+    @Test
+    public void testTokenizerThousandsSeparators() {
+        DerekoDfaTokenizer_de tok = new DerekoDfaTokenizer_de();
+        
+        // Swiss apostrophe format (straight apostrophe)
+        String[] tokens = tok.tokenize("Das kostet 1'000'000 Franken");
+        assertEquals("Das", tokens[0]);
+        assertEquals("kostet", tokens[1]);
+        assertEquals("1'000'000", tokens[2]);
+        assertEquals("Franken", tokens[3]);
+        assertEquals(4, tokens.length);
+        
+        // Swiss apostrophe format (curly apostrophe)
+        tokens = tok.tokenize("Der Preis ist 1'234'567 CHF");
+        assertEquals("Der", tokens[0]);
+        assertEquals("Preis", tokens[1]);
+        assertEquals("ist", tokens[2]);
+        assertEquals("1'234'567", tokens[3]);
+        assertEquals("CHF", tokens[4]);
+        assertEquals(5, tokens.length);
+        
+        // Swiss format with decimal
+        tokens = tok.tokenize("Betrag: 1'234'567.89");
+        assertEquals("Betrag", tokens[0]);
+        assertEquals(":", tokens[1]);
+        assertEquals("1'234'567.89", tokens[2]);
+        assertEquals(3, tokens.length);
+        
+        // Thin space format (U+2009)
+        tokens = tok.tokenize("Population: 1\u2009000\u2009000");
+        assertEquals("Population", tokens[0]);
+        assertEquals(":", tokens[1]);
+        assertEquals("1\u2009000\u2009000", tokens[2]);
+        assertEquals(3, tokens.length);
+        
+        // Narrow no-break space format (U+202F)
+        tokens = tok.tokenize("Value: 1\u202F234\u202F567");
+        assertEquals("Value", tokens[0]);
+        assertEquals(":", tokens[1]);
+        assertEquals("1\u202F234\u202F567", tokens[2]);
+        assertEquals(3, tokens.length);
+        
+        // Thin space with decimal
+        tokens = tok.tokenize("Result: 1\u2009000\u2009000,50");
+        assertEquals("Result", tokens[0]);
+        assertEquals(":", tokens[1]);
+        assertEquals("1\u2009000\u2009000,50", tokens[2]);
+        assertEquals(3, tokens.length);
+    }
 }