Downing was forced to cover for the Frenchman over his 'quenelle' celebration on Saturday.
"The last two days have been an education for all of us," confessed Downing.
"It won't happen again.
"The reaction was not favourable. We've spoken to Nico and the FA will look into it, and we'll have to deal with that. He's aware of the issue. I think he's apologised in terms that he's been misunderstood.
"People see him as a quiet person, people call him moody but I've got to say every day he's come in, I've never seen a mood. He's quiet and articulate. I've no doubts about him as a person.
"He's endeared himself to the group. He always feels he has to contribute on the pitch and we want him to do that, to help us get some results, as he did against West Ham. Football-wise he's got a lot to offer."
Downing added: "In terms of temperament I presume he'll be able to cope. He's gone through a lot in his career. I'll have to talk to him. I wouldn't want to throw him out there if he's unsure about dealing with it."
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