Mine

Alias /error/ "/srv/www/err"

<IfModule mod_negotiation.c>
<IfModule mod_include.c>
    <Directory "/srv/www/err">
        AllowOverride None
        Options IncludesNoExec
        AddOutputFilter Includes html
        AddHandler type-map var
        Order allow,deny
        Allow from all
        LanguagePriority en es de fr
        ForceLanguagePriority Prefer Fallback
    </Directory>

#    ErrorDocument 400 /error/HTTP_BAD_REQUEST.html.var
    ErrorDocument 401 /error/401.html
    ErrorDocument 403 /error/403.html
    ErrorDocument 404 /error/404.html
#    ErrorDocument 405 /error/HTTP_METHOD_NOT_ALLOWED.html.var
#    ErrorDocument 408 /error/HTTP_REQUEST_TIME_OUT.html.var
#    ErrorDocument 410 /error/HTTP_GONE.html.var
#    ErrorDocument 411 /error/HTTP_LENGTH_REQUIRED.html.var
#    ErrorDocument 412 /error/HTTP_PRECONDITION_FAILED.html.var
#    ErrorDocument 413 /error/HTTP_REQUEST_ENTITY_TOO_LARGE.html.var
#    ErrorDocument 414 /error/HTTP_REQUEST_URI_TOO_LARGE.html.var
#    ErrorDocument 415 /error/HTTP_UNSUPPORTED_MEDIA_TYPE.html.var
   ErrorDocument 500 /error/500.html
#    ErrorDocument 501 /error/HTTP_NOT_IMPLEMENTED.html.var
#    ErrorDocument 502 /error/HTTP_BAD_GATEWAY.html.var
    ErrorDocument 503 /error/503.html
#    ErrorDocument 506 /error/HTTP_VARIANT_ALSO_VARIES.html.var
    ErrorDocument 507 /error/507.html