The European Commission said the deal between the world’s largest supplier of eyewear and Europe’s largest optical retail chain could also reduce competition.
It will decide by June 22 whether to clear or block the deal.
“In this consolidating market, we need to carefully assess whether the proposed merger would lead to higher prices or reduced choices for consumers when they visit their local optician,” European Competition Commissioner Margrethe Vestager said in a statement.
Retailers and rival lens makers have voiced concerns to the EU watchdog, sources told.
EssilorLuxottica was formed last year from the merger of French lens maker Essilor and Italian eyewear group Luxottica.