Short notice of position relocation – A U.S. citizen petitioner, living and working abroad, has received a job offer in or reassignment to the United States with little notice for the required start date.
Discretion
The list of examples provided above is not exhaustive. DOS may exercise its discretion to accept local Form I-130 filings for other emergency or exceptional circumstances of a non-routine nature, unless specifically noted below. However, such filings must be truly urgent and otherwise limited to situations when filing with USCIS online or domestically with an expedite request would likely not be sufficient to address the time-sensitive and exigent nature of the situation.
DOS may consider a petitioner’s residency within the consular district when determining whether to accept a filing, but it is not required.[6]
https://www.uscis.gov/policy-manual/volume-6-part-b-chapter-3
I read it that Frankfurt could, they have fairly wide discretion, still think it is a major ask and have never seen it actually happen.