Learn French: Il accepte l'affectation dans notre filiale pour six mois. - He accepts the assignment in our subsidiary for six months.

We use pour followed by a time expression to indicate an intended or planned duration, usually extending into the future. Since the six-month assignment is a plan set in motion by his acceptance today, pour is correct. If we were describing a completed past event, we would use pendant (for example, il a travaillé pendant six mois).

Does affectation mean the same thing as the English word "affection"?

Not in this context! It is a false friend. In business, government, or military contexts, une affectation refers to an "assignment," "posting," or "allocation" to a specific job or location.

What exactly is une filiale?

In the corporate world, une filiale is a "subsidiary" or a branch of a parent company. Despite looking like the English word "filial" (which relates to a son or daughter), it strictly means a subsidiary business here.

Could we say à notre filiale instead of dans notre filiale?

Yes, both are understood, but dans is preferred here because it emphasizes integrating into the company's organizational structure or working inside that specific branch's team. Using à would point to the entity or location in a much more general way.