BERLIN—Tesla, well-versed in German bureaucracy as it tries to build a huge factory near Berlin, is seeking a waiver from COVID-19 rules on mass gatherings to host up to 9,000 people at a “Giga-Fest” to showcase its plans. The electric vehicle maker, which began construction in the town of Grunheide in December 2019 but is still awaiting final approval for its site, announced in August it would hold an event on Oct. 9 to let locals see the factory in construction. Its outspoken boss, Elon Musk, tweeted earlier this month he would attend. Local authorities told Reuters the company had applied for permission to have 9,000 people on-site, beyond pandemic rules which limit such gatherings to 5,000. “The documents available suggest that the application will be approved,” a spokesperson for the local authorities said, confirming an earlier report by newspaper B.Z. Tesla was not immediately available for comment. To host …