S3 - Access object inside “folder” using boto3

Question

Dealing with S3 I know that we don't have such thing as a folder but I will call it that way to try exemplification my problem. The bucket name is "Exemple". Inside the bucket we have "/folder1", inside folder1 we have "/folder2" and inside folder2 we have "/goalFile.csv". I am sure that the problem is not in the access key or in the secret access key. Here it is what I have been trying:

import sys
if sys.version_info[0] <3:
  from StringIO import StringIO #Python 2.X
else:
  from io import StringIO #Python 3.X

client = boto3.client('s3', aws_access_key_id='myKeyID',
                      aws_secret_access_key='mySecretKeyID')
    
bucket_name = 'exemple'
object_key ="/folder1/folder2/goalFile.csv" 

csv_obj = client.get_object(Bucket=bucket_name, Key=object_key)
body = csv_obj['Body']
csv_string= body.read().decode('utf-8')

i got the following error message: "ClientError: An error occurred (SignatureDoesNotMatch) when calling the GetObject operation: The request signature we calculated does not match the signature you provided. Check your key and signing method."