By Pietro Lombardi

Veolia Environnement SA agreed late Wednesday to extend its improved offer to buy a 29.9% stake in waste-management company Suez SA from Engie SA, as requested by Engie shortly before.

The French resource-management company's decision came after Engie welcomed the sweetened offer and said it was in line with its expectations in terms of both price and social guarantees. However, it asked for an extension of the offer to Oct. 5, which Veolia granted.

On Wednesday, Veolia increased its offer to Engie to 18 euros ($21.10) for each Suez share from a previous offer of EUR15.50 a share. Veolia also promised job security for Suez employees in France in the new offer, and said that it wouldn't launch a hostile takeover bid for Suez.

"The board therefore considered that this new offer is in line with its expectations in terms of price and social guarantees," Engie said, responding to the new offer. Besides the extension, it also requested a formal commitment by Veolia to a takeover only on friendly basis.

The bidder agreed to both requests, saying that it will formalize its commitment to a friendly takeover by Oct. 5, when the new offer now expires.

Write to Pietro Lombardi at pietro.lombardi@dowjones.com; @pietrolombard10