PARIS (Reuters) - President Emmanuel Macron suffered his first electoral setback on Sunday when his Republic on the Move (LREM) party won fewer seats than expected in elections for the French Senate.  What was at stake was whether Macron s LREM and allies would win enough seats to give him a three-fifths majority vote in both houses of parliament, which he needs for constitutional reforms, including plans to overhaul parliament.     The vote, in which about 171 of the Senate s 348 seats were up for grabs, consolidated the Senate s existing conservative majority. But the Socialist party, which was crushed in last June s legislative elections, did well in the vote, provisional results provided by the French Senate showed. The results could complicate Macron s plans for constitutional reforms and come as his popularity is declining, just four months after his election in May. His approval ratings have dropped considerably in opinion polls, dragged down by labor reforms and planned budget cuts, including a decrease in housing aid for students.     LREM, which hoped to win 40-50 Senators, ended up securing 23, and will be counting on alliances with lawmakers from other parties to back the government on a case by case basis.  The Senate s conservative majority is now composed of some 150 members of The Republicans party, confirming the Senate as a counterweight to Macron, even if the National Assembly, where Macron has a clear majority, has the final say on legislation.  Voters clearly showed they wanted a parliamentary counterweight, which is in my view vital to a balanced democracy,  Gerard Larcher, the President of the French Senate said in a public address. Macron s LREM was not expected to win a majority partly because of the electoral system. In elections for the Senate, only mayors and regional councilors and not the general public vote and Macron has plans that are unpopular with many local councilors. A number of local officials are unhappy with his plans to cut subsidies to local authorities. Jean Leonetti, a former The Republicans minister said on Twitter:  First setback for Emmanuel Macron . It was not immediately clear if Macron will be able to secure a three-fifths majority in both houses of parliament as it might require negotiations with other groups, including some members of The Republicans party. Macron s party would need 180 seats in the Senate to reach the three-fifths majority in both houses of parliament.     