This is from religionclause.blogspot.com which you can find here:
“In a lawsuit filed this week, the Freedom From Religion Foundation is again challenging the constitutionality of the Internal Revenue Code’s parsonage allowance. The complaint (full text) in Gaylor v. Lew, (WD WI, filed 4/6/ 2016), contends that Section 107 of the Internal Revenue Code–which allows clergy to exclude from taxable income a housing allowance paid as part of their compensation– violates the Establishment Clause. The suit was brought by two FFRF officers who also received housing allowances. One of the plaintiffs is an ordained minister who in prior years when employed by a church was able to claim the allowance. In 2014, the 7th Circuit dismissed a similar suit on standing grounds because plaintiffs had not sought to exclude their FFRF allowances on their federal income tax returns or claim a tax refund. (See prior posting.) This time plaintiffs did file amended returns seeking a refund of taxes paid on their housing allowances. FFRF issued a press release announcing the filing of the lawsuit.”
You can learn more about this issue here.