I would use the phrase "be familiar to" with a person. For example, one might say, "I don't know much about knitting. It is not familiar to me." Although this example doesn't use "be," it is another way I would use the phrase "familiar to." "He looks familiar to me." I would use the phrase "be familiar with" with a subject or a place. For example, "Are you familiar with knitting?" or "He wasn't familiar with London."