G.R. No. 10297 - Bonzon vs. Standard Oil Company of New York

Plaintiffs – two lawyers, a medical practitioner, a public accountant, a dental surgeon, and a pharmacist, suing in their own behalf and on behalf of other professionals practicing in the City of Manila.
Defendants – the Municipal Board of the City of Manila and others.
Prayer – annulment of Ordinance No. 3398 and the Charter provision authorizing it, and refund of taxes paid under protest.

Ordinance No. 3398 (approved July 25, 1950) imposes a municipal occupation tax on various professions (including those of the plaintiffs) and prescribes for non‐payment a fine of up to ₱200, or imprisonment up to six months, or both.
The ordinance was enacted under paragraph (1), section 18 of the Revised Charter of the City of Manila (as amended by R.A. 409), which authorizes the Municipal Board to impose an occupation tax not exceeding ₱50 per annum and “to fix penalties for the violation of ordinances which shall not exceed … two hundred pesos fine or six months’ imprisonment, or both … for a single offense.”

Plaintiffs had already paid the national occupation tax under section 201 of the National Internal Revenue Code; upon refusal to remit the Manila tax, they paid under protest and filed suit in the Court of First Instance of Manila.
The trial court upheld the Charter provision but declared Ordinance No. 3398 void for lack of penalty‐imposing authority. Both parties appealed.

Is the penalty provision in Ordinance No. 3398 authorized by the Manila Charter?
Does Ordinance No. 3398 (and the Charter authorization) amount to unconstitutional class legislation, unjust or oppressive discrimination within the profession, or impermissible double taxation?