a) There is collective bargaining agreement

b) Genuine unions are to weak to force one

c) The employer or a employers association seeks themselves a union and negotiate a agreement

d) In the individual agreements with employees a new clause incorporating the collective agreement is inserted

(It is probably a high fluctuations sector anyway or you can use move the employees to sign new treaties - no union they can complain too)

e) The individual agreement makes the collective agreement legally binding (It would be binding for union members of the contracting union anyway, but we assume few exists)

I can't use "contract"?

Fake unions play a role in temporary work: These slave traders must pay the same wage as the company where the slaves actually work IF THEY DON'T HAVE AN AGREEMENT OF THEIR OWN. So they have fake agreements with fake unions. They get away with it, because so few temp workers are organised in real unions

Worker councils are elected in the companies, but they don't do bargaining and they are banned by law from calling to strike.

There are a few specialised companies though who pay well and who have no interest at all in flexibility of their well trained employees. In all other sectors of the economy precarious employment is becoming the rule as older employees reach pension age. There won't be much of a "dual labour market" soon.