Workers from temporary agencies are in a more precarious situation. They are under pressure to work hard (should they want to "qualify" for permanent employment) and can be sacked easily. Some of them have been active in the union, and IP has tried to get them involved by addressing their specific situation, organizing rallies in front of agency offices, starting collective bargaining processes in the agencies, and including them in the strike ballot--but it remains difficult to bridge the gap created by the dual employment structure.
amazing how similar this is to other industries