Two British Labour Party lawmakers - Bob Ainsworth and Jim Cunningham -and eight employees from the Browns Lane factory in Coventry distributed leaflets and brandished picket signs outside a theatre on Wednesday where Ford held an event to promote its new Focus model.
The US car manufacturing giant was hosting a preview presentation for the new model before the start of the Paris Motor Show on Saturday.
Jaguar said last week it would halt car production at the Browns Lane site in central England, causing the loss of 1 100 jobs.
"Jaguar's home is in Coventry. You mention Coventry, you mention Jaguar in the same breath," said Coventry lawmaker Jim Cunningham.