It seemed innocent enough

When Tasmanian (Australia) member of that states upper house finally announced his intention to run for Mayor of Launceston, he meant to do so in style.
Ivan Dean pledged to donate his potential mayoral salary of $84,000 to charity and youth activities.
"Many people have criticised me for being greedy and wanting to double dip the public purse," he said, referring to his existing parliamentary salary. Dean already earns $104,957 including allowances as a Legislative Councillor.
By holding to his offer, Dean would risk breaching the Local Government Act’s bribery provisions by, essentially, buying votes.
The Act states that a person must not promise, or offer money, in relation to a vote at a poll or the support of a candidate and the Director of Public Prosecutions has decided the matter needs more investigation
"I don't want any controversy, so, of course I will withdraw my offer." A contrite Dean announced.

Putting aside that Dean is a lawmaker, and as such should have a better understanding of the law; this was a noble sounding gesture. There will always be an issue when elected office bearers hold multiple positions.
Apart from the ‘double dipping’ there are also issues of being able to run two offices simultaneously, not to mention the dangers of conflict of interest between the two sectors of government.
Tasmania has often had to face the issue of multiple office holders and perhaps should consider some kind of restriction.
However, the law in this case is quite correct so far as electoral ethics. The other factors being acceptable, the pledge gives Dean an unfair advantage over candidates who are not in a position to donate their salary.
City councils were once, generally voluntary positions, with a small stipend. As city management becomes more complex, the role of councillors has demanded far more time and energy. Hence a reasonable salary often goes with the job.
With that expectation tax payers should, perhaps, expect those who fill these positions to stick with one job at a time. Rather than donate his salary, Dean should consider resigning from parliament to concentrate on his council interests.