As near as I can tell, Mrs Trump never approached her for any "Fashion" assistance or clothes. Her claim to fame is she provided some dresses etc to Michelle Obama.
Mrs. Trump has enough fashion sense to select her own clothing and accessories without the need to patronize a little know French designer.
(Yes I know this has nothing to do with Objectivism or Ayn Rand. I just thought it was funny that she was turning down something she had not even been considered for.)