I'm afraid the issue with your question is that there is no way for an eNotes Educator to know which Anne Friedberg essay to which your instructor is referring. There are a few possibilities (many in the form of articles) that Friedberg has written. Just for the sake of completing your question, I will assume you are speaking of "Les Flaneurs de Mal(l): Cinema and the Postmodern Condition" because of a few aspects of content that appropriately connect with the French documentary The Gleaners and I.
This is especially in reference to Friedberg's ideas on Postmoderism and how they compare to The Gleaners and I. Take, for example, the way that Friedberg introduces her essay. She does so with the following quotation:
Then came up the film and burst this prison-world asunder by the dynamite of the tenth of a second, so that now, in the midst of its far-flung ruins and debris, we calmly and adventurously go traveling.
Even though this quotation is actually by Walter Benjamin, the emphasis is Anne Friedberg's. In fact, it is the quote that she begins her essay on Postmoderninsm. This is very interesting because it relates exactly to The Gleaners and I. It is precisely in this documentary by Agnes Varda that she explores the "far-flung ruins and debris" and discovers how gleaners make these things their treasures. Further Varda "calmly and adventurously [goes] traveling" among these gleaners, as she is a gleaner herself, and discovers many nuances of these special people, especially the fact that many of them are "not poor."
Anne Friedberg continues to use quotations to further her points on Postmoderinsm and cinema, specifically. She uses her own emphasis with italics again here:
With the close-up, space expands; with slow motion, movement is extended. The enlargement of a snapshot does not render more precise what in any case was visible, though unclear: it reveals entirely new formations of the subject.
This is important to The Gleaners and I because precisely of its "new formations of the subject" that Friedberg adds for emphasis and that Agnes Varda appropriately applies in her documentary. Not only does Varda use different camera angles, but she ingeniously uses a new "technique" where she "forgets" to turn off her camera, continues to film the conversation, and captures the nuances of her subjects (including herself) by focusing the visual on what has become "the dance of the lens cap." Varda also focuses a lot on the side aspect of aging because of all of the shots of her new gray hair (that she brushes on film) and of her wrinkling hands.
In regards to what "did you like about the film," I can't answer that question for you; however, I can tell you that I loved the focus of the gleaners in France because I was able to compare it to the way we "glean" in America. Not only have I seen news reports on people gleaning in urban settings (especially behind organic grocery stores), but I "glean" here as part of a church service project (where my Catholic parish gleans fields, often of tomatoes, for the poor in our area).