diff --git a/doc/xmlcatalog_man.xml b/doc/xmlcatalog_man.xml
index 1e0ba5c8..ec9b190c 100644
--- a/doc/xmlcatalog_man.xml
+++ b/doc/xmlcatalog_man.xml
@@ -368,8 +368,8 @@
 		<para><acronym>XML</acronym> catalog behavior can be changed by redirecting
 			queries to the user's own set of catalogs. This can be done by setting
 			the <envar>XML_CATALOG_FILES</envar> environment variable to a space-separated
-			list of catalogs. An empty one should deactivate loading the
-			default <filename>/etc/xml/catalog</filename> catalog.
+			list of catalogs. Use percent-encoding to escape spaces or other characters.
+			An empty variable should deactivate loading the default <filename>/etc/xml/catalog</filename> catalog.
 		</para>
 	</listitem>
 		</varlistentry>
diff --git a/doc/xmllint.xml b/doc/xmllint.xml
index 59a6c727..7d83827c 100644
--- a/doc/xmllint.xml
+++ b/doc/xmllint.xml
@@ -786,8 +786,8 @@
 		<para><acronym>XML</acronym> catalog behavior can be changed by redirecting
 			queries to the user's own set of catalogs. This can be done by setting
 			the <envar>XML_CATALOG_FILES</envar> environment variable to a space-separated
-			list of catalogs. An empty one should deactivate loading the
-			default <filename>/etc/xml/catalog</filename> catalog.
+			list of catalogs. Use percent-encoding to escape spaces or other characters.
+			An empty variable should deactivate loading the default <filename>/etc/xml/catalog</filename> catalog.
 		</para>
 	</listitem>
 		</varlistentry>