From Bearing Arms:

With the fair set to kick off in less than a month, Paxton followed through on his threat on Thursday by suing the city and the state fair in district court. Paxton is asking the court to block the ban through both temporary and permanent injunctions, arguing that while While some portions of Fair Park are “gun-free zones” as established by state statute, the “vast majority of the 277-acre Fair Park in Dallas is not a place where weapons or firearms are prohibited.” 

If the fair moves forward with its carry ban, Paxton says lawful gun owners are either subject to arrest, or are going to be forced to comply with an unlawful rule in order to enter the fair.