Or maybe he just put up shop there w/o asking and said she let him do it...(the most likely scenario)...
If the above scenario is correct, then my theory is still quite possible that Landa and Shossana spoke again. Finding Landa sitting in her
office with out her
permission most probably scared her off. But even if Shossana was avoiding Landa, Landa most probably took every opportunity he could to speak to her and creep her out.I just can't accept the fact that Landa would let go of Shossana so easily. Being the Sherlock-Holmes-detective that Landa happens to be, I'm 100 percent certain that Landa investigated "Emmanuelle Mimieux's" background and found a lot of clues pointing to the fact that the real Emmanuelle Mimieux was dead, and done further investigation to figure out who was the young girl who had taken on "madam Mimieux" as her alias, and found some information which indicated to him that this was the same Shossana who escaped from him four years ago.
Remember that Landa is a sadist. He likes playing mind-games with his victims. Which is why I find it very hard to believe that he would let go of Shossana so easily after realizing that she was alive after everything that happened to her and her family four years ago because of Landa. Which is why I'am lead to the conclusion that he most probably spoke to her again to creep her out as much as possible, and gaining access to Shossana's office was one such opportunity that Landa used to speak to her again. Also lets not forget that Landa is in charge of the security in the theater. He was most probably hanging around the theater for quite some time (I'm assuming at least a few weeks) before the screening of the movie took place. Such a scenario is ripe with a lot of opportunities for Landa to confront Shossana.