BRUSSELS (Reuters) - EU antitrust regulators will decide by Oct. 26 whether to clear French telecoms operator Iliad’s 3.5-billion-euro ($4.1 billion) bid for Polish mobile group Play, a filing on the European Commission’s website showed on Tuesday. The deal would make Iliad, controlled by French tycoon Xavier Niel, Europe’s sixth largest mobile operator, marking its continued expansion outside France. The Commission can either clear the deal with or without concessions or it can open a four-month investigation if it has serious concerns. Iliad sought EU approval for the deal on Monday. Play is the No. 1 mobile operator in Poland with a 29% market share of users, thanks to its aggressive prices and a strategy similar to Iliad, whose low-cost mobile offers shook up the French market nearly a decade ago. ($1 = 0.8522 euros)