The municipal tourist tax is charged per guest per night and is paid directly to the accommodation provider. Hotels, holiday apartments and group accommodation: adults CHF 3.50/night; children aged 6–16 CHF 1.75/night. Camping: adults CHF 2.80/night; children aged 6–16 CHF 1.40/night. The highest standard adult rate is therefore CHF 3.50 per person per night. Separately, the Canton of Bern levies CHF 1.00 per night for adults as a tourism-promotion charge, payable by the accommodation provider.
Children under 6 are exempt from the municipal tourist tax. Reduced rates apply to children aged 6–16: CHF 1.75 per night in hotels, holiday apartments and group accommodation, and CHF 1.40 per night at campsites. The page states no other exemptions or reductions. Separately, Bern Canton charges an additional CHF 1.00 per night for adults for tourism promotion; this is payable by the accommodation provider.
The official page does not state a separate Airbnb or short-term-rental rule. It does expressly include holiday apartments in the standard tourist-tax category, so the general holiday-apartment rates apply where relevant.