The following ACI allow anonymous read, search and compare on select attributes of inetOrgPerson entries while authenticated users can access several more. The authenticated user will inherit the privileges of the anonymous ACI. In addition, the authenticated user can change userPassword:

aci: (targetattr="objectclass || uid || cn || mail || sn || givenName")(targetfilter="(objectClass=inetorgperson)")
(version 3.0; acl "Anyone can access names and email addresses of entries representing people";
allow (read,search,compare) userdn="ldap:///anyone";)
aci: (targetattr="departmentNumber || manager || isMemberOf")(targetfilter="(objectClass=inetorgperson)")
(version 3.0; acl "Authenticated users can access these fields for entries representing people";
allow (read,search,compare) userdn="ldap:///all";)
aci: (targetattr="userPassword")(version 3.0; acl "Authenticated users can change password";
allow (write) userdn="ldap:///all";)

If no unauthenticated access should be allowed to the Directory Server, the preferred method for preventing unauthenticated, or anonymous access is to set the Global Configuration property reject-unauthenticated-requests to true.