diff --git a/grammar/query.pp b/grammar/query.pp
index a4ef731ea4..9511c417fe 100644
--- a/grammar/query.pp
+++ b/grammar/query.pp
@@ -30,9 +30,9 @@
 %token  collection      collection
 %token  type            type
 %token  id              id|recordid
-%token  field_prefix    field.
-%token  flag_prefix     flag.
-%token  meta_prefix     meta.
+%token  field_prefix    field\.
+%token  flag_prefix     flag\.
+%token  meta_prefix     meta\.
 %token  true            true|1
 %token  false           false|0
 %token  word            [^\s\(\)\[\]:<>≤≥=]+
diff --git a/tests/Alchemy/Tests/Phrasea/SearchEngine/resources/queries.csv b/tests/Alchemy/Tests/Phrasea/SearchEngine/resources/queries.csv
index ff207a8f82..b29461a7c2 100644
--- a/tests/Alchemy/Tests/Phrasea/SearchEngine/resources/queries.csv
+++ b/tests/Alchemy/Tests/Phrasea/SearchEngine/resources/queries.csv
@@ -105,6 +105,11 @@ true|<text:"true">
 # Metadata (EXIF or anything else) matcher
 meta.MimeType:image/jpeg|<metadata:MimeType value:"image/jpeg">
 
+# Unescaped "." issue on key prefixes
+fieldOne:foo|(<field:fieldOne> MATCHES <text:"foo">)
+flagged:true|(<field:flagged> MATCHES <text:"true">)
+metadata:foo|(<field:metadata> MATCHES <text:"foo">)
+
 # Matcher on unknown name --> fulltext
 foo:bar|(<field:foo> MATCHES <text:"bar">)
 foo:bar AND baz|((<field:foo> MATCHES <text:"bar">) AND <text:"baz">)