Hi 
   need to setup an acl restriction based on   targetfilter like 

(targetattr = "*") (targetfilter= "(!(Affectation=testaff))") (version 3.0;acl "Student restriction Acl";allow (write)(groupdn = "ldap:///cn=Students Manager,ou=Groups,dc=example,dc=com");)

this  rule hide all the student branch 
        ou=Students,ou=People,dc=lagh-univ,dc=dz
on witch it is applied

need to hide only certain people form student banch for cn=Students Manage  

pepole that havn't (Affectation=testaff) attribute

thank's