diff --git a/exceptions/MDImporterMissingConcordance.php b/exceptions/MDImporterMissingConcordance.php
index 93252e9..28819db 100644
--- a/exceptions/MDImporterMissingConcordance.php
+++ b/exceptions/MDImporterMissingConcordance.php
@@ -70,7 +70,7 @@ final class MDImporterMissingConcordance extends Exception {
 
         }
 
-        $exception = new MDImporterMissingConcordance("Unmapped specific value of type " . $target_type . ": " . $value_to_map . PHP_EOL . "Please consult https://concordance.museum-digital.org for filling out missing concordances");
+        $exception = new MDImporterMissingConcordance("Unmapped specific value of type " . $target_type . ": '" . $value_to_map . '\'' . PHP_EOL . "Please consult https://concordance.museum-digital.org for filling out missing concordances");
         $exception->target_type = $target_type;
         $exception->value_to_map = $value_to_map;