In chapter six, of Mary Shelley's Frankenstein, Elizabeth decides to "relate her [Justine's] history" for Victor. Elizabeth is writing Victor to tell him of their family since he has been gone (to study and complete his desire to reanimate life) for so long.
Justine had come to live with the Frankenstein's after the death of her father and the mistreatment of her mother. Caroline Frankenstein, Victor's mother, could not stand to see children not taken care of (as seen with Elizabeth's adoption). Justine had been by Caroline's mother's side the same way which both Elizabeth and Victor had (and this had put Justine in a special place in Elizabeth's heart).
After Caroline's death, Justine's siblings all passed away. Driven by guilt, Justine returned to her mother's side (her mother's Roman Catholic beliefs forced her to believe that the deaths of her favorite children were the consequences of her mistreatment of Justine). After her return, Justine's mother still mistreated her and blamed her for the deaths of her siblings. After Justine's mother's death, Justine returned to the Frankenstein household.
While she returned to be a servant, Elizabeth states that things were very different for servants in Geneva than they were in the households of France and England.
Justine, thus received in our family, learned the duties of a servant; a condition which, in our fortunate country, does not include the idea of ignorance, and a sacrifice of the dignity of a human being.
Therefore, Justine was treated well and educated.
Justine was not of Swiss descent. The chapter states that Victor's brother, Ernest wishes to be Swiss.
He is now sixteen, and full of activity and spirit. He is desirous to be a true Swiss, and to enter into foreign service.
Therefore, Justine's position in Swiss society does not exist. Instead, she is of either English or French descent (denoted through Elizabeth's letter). Regardless, her position in her homeland was not high by any means. Her mother's abusive treatment of her lowered her to that of a slave (given her abuse). Her position in the Frankenstein household, on the other hand, was raised given her place in the family was respected. Although she was technically a servant, she was not treated as such.