Yes. In every negotiations you have a taxed service or product. When you offer your services or sell your products you have to open a company on the respective governmental organ to operate legally and every sale made you have to notify the government about that. So, the taxes will be applied over your sales, doesn't matter if the customer used fiat or Bitcoin to conclude the negotiation.

Moreover, when you buy a product, usually taxes are already inserted on its final price. When you use Bitcoin to make a purchase you are already paying taxes automatically. There is no way to avoid this.