I can't prove this, because I can't find a case in which FNP is explained, but by analogy I am fairly confident this is right.

First, there are indeed a couple of Spanish sites with franchise conditions that include FNP, and it's clearly an expense. It comes after the monthly royalty fee, as in yours.

Others have a category in the same position called "Canon de publicidad"; for example:

"Royalty mensual:
304,20 € en concepto de soporte y apoyo permanente, supervisión y control periódico de la franquicia.
Canon de Publicidad Corporativo:
200€ mensuales + aportación de 500 €anuales"
http://www.nomasvello.es/franquiciasdepilacioncondiciones

And here it's "publicidad nacional", which must refer to common advertising for the whole chain of franchisees:
"Existen dos royalties a pagar a Curves®:
1. Uno del 6% mensual sobre tus ingresos brutos, por el uso de nuestros logotipos, marcas y sistemas, pero con limitaciones (le cobraremos como mínimo: 395€, y como máximo 795€); ambas cantidades, más IVA.
2. Otro del 6% mensual por la publicidad nacional."
http://www.curveseurope.com/precio-franquicia-curves/

Now, in this one, from Colombia, we have a "Fondo Nacional de Publicidad":

Aporte total mensual de regalías 10%
(8% regalías de operación con aporte mínimo de USD500 y 2% aporte al Fondo Nacional de Publicidad con un mínimo de USD250)"
http://dc400.4shared.com/doc/Kj92UcoM/preview.html

And National Advertising Fund is a standard charge for franchisees in English:

"As part of many agreements, franchisors require their franchisees to contribute to a national advertising fund that pays for the development and placement of ads for the company."
http://www.entrepreneur.com/article/50100

Here's Century 21 again, the same company as the Colombian example just quoted, but in English:

"Royalty Fee 6% of your Gross Revenue
Minimum Monthly Royalty Fee $500 per month
Brokers Council Fees Varies by location
National Advertising Fund ("NAF") Fees 2% of monthly Gross Revenue, subject to a monthly minimum and maximum ($651/$1,508 through May 31, 2012)."
http://www.franchisedirect.com/realestatefranchises/century-...

So I reckon this is very probably Fondo Nacional de Publicidad.