Collections+Unicode.h

@interface NSDictionary (Unicode)
- (NSString *)unicodeDescription;
- (NSString *)unicodeDescription:(int)level;
@end

@interface NSArray (Unicode)
- (NSString *)unicodeDescription;
- (NSString *)unicodeDescription:(int)level;
@end

Collections+Unicode.m

@implementation NSDictionary (Unicode)

- (NSString *)unicodeDescription {
    return [self unicodeDescription:0];
}

- (NSString *)unicodeDescription:(int)level {
    NSMutableString *prefix = [[NSMutableString alloc] init];
    for (int i = 0; i < level; i++) {
        [prefix appendString:@"    "];
    }

    NSMutableString *str = [[NSMutableString alloc] init];
    
    [str appendFormat:@"%@{\n", prefix];
    
    for (id key in self) {
        [str appendFormat:@"%@    %@ = ", prefix, key];
        
        id val = self[key];
        NSString *valStr;
        if ([val isKindOfClass:[NSDictionary class]]) {
            valStr = [(NSDictionary *)val unicodeDescription:level + 1];
        } else if ([val isKindOfClass:[NSArray class]]) {
            valStr = [(NSArray *)val unicodeDescription:level + 1];
        } else {
            valStr = [val description];
        }
        
        [str appendFormat:@"%@;\n", valStr];
    }
    
    [str appendFormat:@"%@}", prefix];
    
    return str;
}

@end


@implementation NSArray (Unicode)

- (NSString *)unicodeDescription {
    return [self unicodeDescription:0];
}

- (NSString *)unicodeDescription:(int)level {
    NSMutableString *prefix = [[NSMutableString alloc] init];
    for (int i = 0; i < level; i++) {
        [prefix appendString:@"    "];
    }
    
    NSMutableString *str = [[NSMutableString alloc] init];
    
    [str appendFormat:@"%@(\n", prefix];
    
    for (id val in self) {
        [str appendFormat:@"%@    ", prefix];
        
        NSString *valStr;
        if ([val isKindOfClass:[NSDictionary class]]) {
            valStr = [(NSDictionary *)val unicodeDescription:level + 1];
        } else if ([val isKindOfClass:[NSArray class]]) {
            valStr = [(NSArray *)val unicodeDescription:level + 1];
        } else {
            valStr = [val description];
        }
        
        [str appendFormat:@"%@,\n", valStr];
    }
    
    [str appendFormat:@"%@)", prefix];
    
    return str;
}

@end

Example.m

#import "Collections+Unicode.h"

NSLog(@"%@", [@{@"céréales": @"hi", @"test": @[@1, @"1"]} unicodeDescription]);