http://www.skysports.com/football/news/11095/9841963/inter-milan-roma-and-monaco-punished-for-breaking-ffp-rules
http://romapress.us/2017/04/21/uefa-roma-comply-ffp-targets/
From UEFA's website:
http://www.uefa.com/community/news/newsid=2064391.html
4) Are clubs automatically excluded if they are not in line with FFP?
If a club is not in line with the regulations, it will be UEFA's Club Financial Control Body that decides on measures and sanctions.
Non-compliance with the regulations does not mean that a club will be excluded automatically, but there will be no exceptions. Depending on various factors (e.g. the trend of the break-even result) different disciplinary measures may be imposed against a club. There is a catalogue of measures:
a) warning
b) reprimand
c) fine
d) deduction of points
e) withholding of revenues from a UEFA competition
f) prohibition on registering new players in UEFA competitions
g) restriction on the number of players that a club may register for participation in UEFA competitions, including a financial limit on the overall aggregate cost of the employee benefits expenses of players registered on the A-list for the purposes of UEFA club competitions
h) disqualification from competitions in progress and/or exclusion from future competitions
i) withdrawal of a title or award
In addition the CFCB have decided in numerous cases that the objectives of FFP can be best achieved by taking a rehabilitative approach rather than a punitive approach. This has led to the conclusion of settlement agreements between a club and the CFCB, combining certain financial contributions with numerous restrictive conditions, which provide a roadmap for clubs to reach break-even in the foreseeable future
TL;DR, This will be the 2nd time if they didn't comply and would probably result in severe ramifications