In order to know whether a merchant needs to collect Louisiana sales taxes, he should take the time to read either online or in hard copy the requirements and exemptions for assessment of Louisiana sales taxes. One of the biggest questions that one may ask is how Louisiana sales taxes apply to Internet sales.
In short, it is applied in the same way as catalog sales—if the merchant has a physical presence in Louisiana or delivers physically to Louisiana with their own trucks, the purchase is subject to Louisiana sales taxes. Of course, you expect the merchant to collect the sales tax, but if he doesn’t, the buyer is liable to report the purchase and applicable sales tax. If you fail to do so, and the state of Louisiana finds out about your purchase, they have the right to bill you or the seller for the purchase.