Is the word franco the same in Brazilian and European Portuguese?

Yes

The word "franco" is semantically and grammatically identical in both Brazilian and Continental Portuguese. It retains the same meanings: as an adjective meaning "honest," "direct," or "straightforward"; as an adjective meaning "free" or "exempt" (e.g., franco de impostos); and as a noun referring to the historical Frankish people or a currency. There are no differences in spelling or the core definition. The only differences are phonetic (the pronunciation of the vowels and the way consonants are articulated) and the grammatical context of the surrounding sentence (such as the choice of pronouns like você in Brazil vs. tu in Portugal).

Brazilian Portuguese Examples

1. Eu serei muito franco com você sobre esse problema. (I will be very frank with you about this problem.)
2. O preço do produto está franco de taxas alfandegárias. (The product price is free of customs fees.)
3. Ele é um homem franco e muito direto. (He is a frank and very direct man.)
4. O franco-atirador estava posicionado na torre. (The sniper was positioned in the tower.)
5. Preciso de uma resposta franca agora. (I need a frank answer now.)

Continental Portuguese Examples

1. Eu serei muito franco contigo sobre esse problema. (I will be very frank with you about this problem.)
2. O preço do produto está franco de taxas alfandegárias. (The product price is free of customs fees.)
3. Ele é um homem franco e muito direto. (He is a frank and very direct man.)
4. O franco-atirador estava posicionado na torre. (The sniper was positioned in the tower.)
5. Preciso de uma resposta franca agora. (I need a frank answer now.)