Werner had a topsy-turvy season in his debut campaign in England following a £47m move from RB Leipzig to Chelsea in the off-season.
The 25-year-old lost his scoring touch, only managing 12 goals in all competitions while laying on 15 assists for his teammates.
Werner had the last laugh though as he helped the Blues to UEFA Champions League glory with victory over Manchester City last month.
"Timo has changed country, club, playing in a new league," Boateng told BILD. "It is not so easy. Nonetheless, he scored his goals, provided assists, was present, went through a hollow and came out and now he’s the Champions League winner.
"For me, it has been a positive season with the usual ups and downs. It makes him bigger and stronger and he learns from it.
"At the Euros, we will see another Timo Werner, a hungry Timo. A Timo with more arrogance, because he has just won the Champions League. It carries you. He will show who he really is."
Germany are in a group with world champions France, European champions Portugal and Hungary, with the top two guaranteed a place in the knockout stages while the third placed side could also sneak through as one of four best third-placed sides from the six groups.
