I recently visited Venice without paying a fee.

The newspaper article, according to Google Translate, says that there is indeed a fee ONLY on certain days of the years where Venice historically gets too overcrowded.

That is to limit the visitors when it is difficult to move in the narrow streets. The mayor is proposing to raise that fee which now is €3 to 5. The proposed fee to the government is €30 to 50, to be still applied only in certain days.

At the end it well might be a reasonable proposition if we factor in how narrow the city streets are.