French Naming Law (Prior to 1993)

From what I've read, there was a restriction on what parents could name their French-born children prior to 1993.

I wish I could get a list of these names, but I am under the assumption that they would all be French versions.

I have a predicament where I have a character who was born in 1961. Her family is Italian in origin and would have named her the Italian form Teresa. Originally, my plan was for her to be born in Italy and moved to France as a child; however, this leads me to another problem as my character is also a cop which requires her to have French nationality.

I would like to know if there's any sort of loophole I can use to keep her as Teresa? Or must I use Thérèse as her legal name and have her family call her Teresa as a workaround?

Any help is appreciated. Thanks in advance.

I believe I have found my answer. Though there is a difference between nationality and citizenship in France, nationality can be obtained by foreigners through several means as neandermagnon suggested. The use of the term nationality instead of citizenship is what had me confused.