diff --git a/lapis-e2e/test/aminoAcidSequence.spec.ts b/lapis-e2e/test/aminoAcidSequence.spec.ts
index 0f833fb5f..fe2c58a09 100644
--- a/lapis-e2e/test/aminoAcidSequence.spec.ts
+++ b/lapis-e2e/test/aminoAcidSequence.spec.ts
@@ -190,7 +190,7 @@ describe('The /alignedAminoAcidSequence endpoint', () => {
 
       const errorResponse = await response.json();
       expect(errorResponse.error.detail).to.match(
-        /Error from SILO: The table does not contain the SequenceColumn 'unknownGene'/
+        /Error from SILO: The table does not contain the field unknownGene/
       );
     });
 
diff --git a/lapis/src/main/antlr/org/genspectrum/lapis/model/advancedqueryparser/AdvancedQuery.g4 b/lapis/src/main/antlr/org/genspectrum/lapis/model/advancedqueryparser/AdvancedQuery.g4
index 9e2dbe183..f2cab6ac3 100644
--- a/lapis/src/main/antlr/org/genspectrum/lapis/model/advancedqueryparser/AdvancedQuery.g4
+++ b/lapis/src/main/antlr/org/genspectrum/lapis/model/advancedqueryparser/AdvancedQuery.g4
@@ -84,7 +84,7 @@ value: name | QUOTED_STRING;
 dateOrNumber: digit+;
 digit: NUMBER | MINUS | DOT;
 name: charOrNumber+;
-charOrNumber: A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z | NUMBER | MINUS | UNDERSCORE | DOT | ASTERISK;
+charOrNumber: A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z | NUMBER | MINUS | UNDERSCORE | DOT | ASTERISK | UNICODE_LETTER;
 
 isNullQuery: isnull_ '(' name ')';
 isnull_: I S N U L L ;
@@ -122,6 +122,7 @@ UNDERSCORE: '_';
 DOT: '.';
 ASTERISK: '*';
 QUOTED_STRING: '\'' ( '\\' . | ~['\\] )* '\'';  // matches all strings with quotes, supports backslash escaping (e.g. \' for a literal single quote, \\ for a literal backslash)
+UNICODE_LETTER: [\p{Letter}] ; // matches non-ASCII Unicode letters and combining marks (e.g. umlauts, accented characters)
 AND: ' ' A N D ' '; // space is important here, otherwise metadataNames with 'AND' in them would be misinterpreted
 OR: ' ' O R ' ';
 NOT: N O T ' ';
diff --git a/lapis/src/test/kotlin/org/genspectrum/lapis/model/AdvancedQueryFacadeTest.kt b/lapis/src/test/kotlin/org/genspectrum/lapis/model/AdvancedQueryFacadeTest.kt
index 6c376e897..4d1322f12 100644
--- a/lapis/src/test/kotlin/org/genspectrum/lapis/model/AdvancedQueryFacadeTest.kt
+++ b/lapis/src/test/kotlin/org/genspectrum/lapis/model/AdvancedQueryFacadeTest.kt
@@ -341,6 +341,11 @@ class AdvancedQueryFacadeTest {
                     query = "some_metadata.regex='it\\'s'",
                     expected = StringSearch("some_metadata", "it's"),
                 ),
+                ValidTestCase(
+                    description = "unquoted regex with non-ASCII characters",
+                    query = "some_metadata.regex=Graubünden",
+                    expected = StringSearch("some_metadata", "Graubünden"),
+                ),
             ),
             invalid = listOf(
                 InvalidTestCase(
@@ -625,6 +630,41 @@ class AdvancedQueryFacadeTest {
                     query = "some_metadata='Côte d\\'Ivoire'",
                     expected = StringEquals("some_metadata", "Côte d'Ivoire"),
                 ),
+                ValidTestCase(
+                    description = "string equals with unquoted umlaut (ü)",
+                    query = "some_metadata=Zürich",
+                    expected = StringEquals("some_metadata", "Zürich"),
+                ),
+                ValidTestCase(
+                    description = "string equals with unquoted accented character (â)",
+                    query = "some_metadata=Neuchâtel",
+                    expected = StringEquals("some_metadata", "Neuchâtel"),
+                ),
+                ValidTestCase(
+                    description = "string equals with unquoted cedilla (ç)",
+                    query = "some_metadata=Français",
+                    expected = StringEquals("some_metadata", "Français"),
+                ),
+                ValidTestCase(
+                    description = "string equals with unquoted tilde-n (ñ)",
+                    query = "some_metadata=España",
+                    expected = StringEquals("some_metadata", "España"),
+                ),
+                ValidTestCase(
+                    description = "string equals with unquoted Cyrillic characters",
+                    query = "some_metadata=Москва",
+                    expected = StringEquals("some_metadata", "Москва"),
+                ),
+                ValidTestCase(
+                    description = "string equals with unquoted Chinese characters",
+                    query = "some_metadata=北京",
+                    expected = StringEquals("some_metadata", "北京"),
+                ),
+                ValidTestCase(
+                    description = "string equals with unquoted mixed ASCII and non-ASCII",
+                    query = "some_metadata=Graubünden",
+                    expected = StringEquals("some_metadata", "Graubünden"),
+                ),
                 ValidTestCase(
                     description = "string equals with escaped backslash in value",
                     query = "some_metadata='back\\\\slash'",
@@ -726,6 +766,16 @@ class AdvancedQueryFacadeTest {
                     "floatField=notAFloat",
                     "'notAFloat' is not a valid float",
                 ),
+                InvalidTestCase(
+                    description = "non-ASCII field name",
+                    query = "divïsion=Bern",
+                    expected = "Metadata field divïsion does not exist",
+                ),
+                InvalidTestCase(
+                    description = "non-ASCII field name with regex suffix",
+                    query = "divïsion.regex=Bern",
+                    expected = "Metadata field divïsion does not exist",
+                ),
             ),
         )
 
@@ -797,6 +847,11 @@ class AdvancedQueryFacadeTest {
                     query = "invalidGene:501Y",
                     expected = "invalidGene is not a known segment or gene",
                 ),
+                InvalidTestCase(
+                    description = "named mutation with non-ASCII gene/segment name",
+                    query = "Ñ:123A",
+                    expected = "Ñ is not a known segment or gene",
+                ),
                 InvalidTestCase(
                     description = "'-' in nucleotide 'from' position is invalid",
                     query = "-300A",