Like many Democrat candidates running for President in 2020, New York City Mayor Bill de Blasio has been an active proponent of campaign finance reform. According to OpenSecrets, "When he served as New York City’s public advocate in 2010, he penned an article in The Nation condemning Citizens United and called on state and local leaders across America to join him..."

And, like other 2020 Democrats, he doesn't think that the existing rules apply to him. 

As reported by the New York Post, de Blasio has been less than ethical in his administration of campaign accounts while demanding accountability from others. 

Strapped for cash, Mayor Bill de Blasio turned to a state political account he controls to buy plane tickets, pay rent and purchase digital advertisements for his nascent presidential campaign — potentially violating campaign finance regulations, campaign finance experts told The Post.

de Blasio's federal campaign account disclosed that it owes the state account nearly $53,000 despite federal law imposing limits on $2,800 being given from state groups to a federal campaign per cycle. 

NY Fairness PAC’s, which is de Blasio's state campaign arm, recorded purchases for de Blasio's Presidential campaign that included:

• $40,000 in digital media consulting services purchased on May 15, the day before de Blasio’s launch;
• $8,562 for “launch weekend travel,” including $3,970.70 in plane tickets bought on United Airlines, American Airlines and JetBlue Airways on May 16 and May 17;
• $4,200 for rent at The Yard, the Brooklyn coworking space where de Blasio’s campaign is headquartered, which was paid in June.

Interestingly enough, the Presidential campaign tracked those purchases as campaign debt, rather than contributions or expenditures. 

“It appears de Blasio’s state PAC spending is in excess of federal limits,” said Tyler Cole, a top lawyer at Issue One, a Washington, DC, watchdog group that focuses on campaign finance reform. “Federal candidates must run their campaigns out of federally regulated committees — the law is only meaningful if they abide by the federal limits.”

Naturally, though, this wouldn't be de Blasio's first run-in with ethical violations.