The Swiss Football League's disciplinary commission said it had fined the club 25,000 Swiss francs ($27,686) for a "violation of the rules concerning publicity on team shirts."
Sion had previously been fined 20,000 Swiss francs for the same offence.
The SFL said in the match against FC Zurich on March 3, Sion's shirts had displayed the message "Solidarity between cantons", having used the slogan "Tourism equals jobs" in a previous game in February.
Both messages appeared to be a reference to a referendum held on March 11 in which Swiss voters narrowly approved a proposal from an environmental group to limit the building of holiday homes, seen by many as a blight in Alpine villages.
Sion were kicked out of the Europa League this season for fielding players they had signed while subject to a transfer ban in July and August last year.
The club's volatile president Christian Constantin took the case to a civil court, defying FIFA and UEFA statutes, and Switzerland was threatened with an international ban unless action was taken against Sion.
Having lost their case, Sion were deducted 36 points and are now bottom of the league.
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