The 23-year-old joined the French club last summer from Torino, where he had been a Serie A regular.
Almiron, 24, has been a target of the Premier League club and the sources say the terms of the deal are almost agreed, while adding it's not over the line yet.
"I am very happy to be here", he stated.
"I know that Newcastle is a big and historic club", said the former Italy under-21 worldwide. "I have accepted this challenge with a great deal of enthusiasm and I can't wait to start".
One man who knows a lot about the Paraguayan playmaker is South American football expert Tim Vickery, who has gushed over Almiron in a quick low-down for Newcastle fans on their imminent signing.
Barreca also landed in Newcastle last night and is believed to have completed his medical also.
News of progress arrived hours before the Magpies were due to entertain Premier League champions Manchester City at St James' Park and a day after Benitez, who is out of contract at the end of the season, had refused to give any guarantees over his future as he awaited progress.
"He has the attributes, he has the quality and he has the characteristics that we look for".