I already tested the regular expression:
sm_macro "users_macro" "{auth_authen}" /user1|user2/
and it seems to work well, so now my definitive config will be:
list "MY_NETWORKS" addr { 158.227.4.0/24}
ratelimit "limite_1H" rcpt 200 / 1h key "%M{auth_authen}"
sm_macro "null" "{auth_authen}" unset
sm_macro "users_macro" "{auth_authen}" /user1|user2/
racl blacklist not sm_macro "null" not sm_macro"users_macro" not list "MY_NETWORKS" ratelimit "limite_1H" msg "Quota exceeded"
Maren